executive summary - political science · richard j. samuels is ford international professor of...

executive summary

This chapter examines the future of Japan’s hedged dependence on U.S. extended deterrence and encourages more imaginative thinking about potential outcomes and strategic implications as the second nuclear age unfolds.

main argument:• With the U.S. nuclear umbrella shrinking and nuclear threats in

Asia becoming greater and more complex, analysts cannot dismiss a nuclear-armed Japan as a purely academic exercise.

• WhilewedonotexpectaJapanesenuclearbreakoutinthenearterm,Washington’s traditional reassurances—massivenumbersofweaponsdeployedintheaterandarobustregionalpresence—havegivenwaytoalessconvincingrelianceonspecificweaponsystemsamidadiminishingconventional military advantage.

• Enhancedbilateraldialoguehasbeenusedtostrengthenthealliance,but Japan’s neighborhood is more dangerous than ever, and the many domesticconstraintsonJapanesenuclearbreakout—cultural,political,andinstitutional—couldbecomelessrestrictivethanbefore.

policy implications:• AU.S.decisiontosustainextendeddeterrencewillrequiresignificantly

more resources and attention than heretofore assigned.

• Amoreintegrated,alliance-basedapproachtodeterrencemightthereforebecome attractive.

• AlternativestoJapan’slong-practicednuclearhedgemaycometohaveappealinTokyoorWashington.

• CoordinatedregionalactiontolimitNorthKorea’snucleardevelopmentremains critical.

Japan

Japan’sNuclearHedge: Beyond “Allergy” and Breakout

Richard J. Samuels and James L. Schoff

Japanesestrategistshavelongbeenambivalentaboutnuclearweapons.Ontheonehand,memoriesofhorrificnuclearattacksonHiroshimaandNagasakihavesustainedanti-nuclearsentimentandhelpedjustifynationalpolicies championing nonproliferation and forgoing an indigenous nuclear arsenal. This “nuclear allergy” has been diagnosed as a genetic condition, and associated institutional and diplomatic constraints on nuclear breakout have beeninvokedtopredictthatJapanwillfinditvirtuallyimpossibletoreversecourseonnuclearweapons.

Japan’snon-nuclearbonafidesarewellestablished.Untilitsrevisionin2012,Article2ofJapan’sAtomicEnergyBasicLaw(1955)statedclearlythatresearch,development,andutilizationofatomicenergywaslimitedtopeaceful purposes.1JapanjoinedtheInternationalAtomicEnergyAgency(IAEA)in1957andhasgenerouslysupportedtheagency’swork.After

1The2012amendmenttothelawadds“nationalsecurity”asoneofseveralreasonswhynuclearsafetyshouldbeguaranteed.Althoughthegovernmentandindividuallawmakersclaimthisadditiondoesnotconflictwiththe“peacefuluse”ofnuclearenergy,therevisedlawisarguablylessclearonthispoint.See,forexample,“‘NationalSecurity’AmendmenttoNuclearLawRaisesFearsofMilitaryUse,” Asahi Shimbun, June 21, 2012.

Richard J. Samuels isFordInternationalProfessorofPoliticalScienceandDirectoroftheCenterfor International Studies at theMassachusetts Institute of Technology. He can be reached at<[email protected]>.

James L. Schoff isaSeniorAssociateintheAsiaProgramattheCarnegieEndowmentforInternationalPeace.Hecanbereachedat<[email protected]>.

TheauthorsaregratefultoMarkBell,AlisonChang,andKuniShimojifortheirresearchassistanceandtocolleaguesJamesActon,VipinNarang,andChristopherTwomeyfortheirreviewofanearlydraft.

234 • StrategicAsia2013–14

considerabledebateanddelay—andthereceiptfromtheUnitedStatesofmuchgreaterlatitudefornuclearfuelhandlingandreprocessing—JapanratifiedtheNuclearNon-ProliferationTreaty(NPT)in1976andsupportedthetreaty’sindefiniteextensionin1995.JapanalsoratifiedtheComprehensiveNuclearTestBanTreatyin1997andwasthefirsttosigntheIAEA’sAdditionalProtocolin1998,allowingastricterregimenforIAEAinspectionsofJapanesenuclear facilities.

Consequently,itwassurprisingtosomein2013whenJapandeclinedtojoin74othernationsandsignastatementinadvanceofthenextNPTreviewstatingthatnuclearweaponsareinhumaneandshouldnotbeusedunderany circumstance.2 This illuminates the other, more realistic side of Japan’s approachtonuclearweapons.TheJapanesegovernmentdoesindeedbelievethatsomecircumstancesmightwarranttheacquisitionanduseofnuclearweapons,andthefactthatJapan’sabilitytoactonthisbeliefrestssolelyinU.S. hands is unnerving for certain politicians and bureaucrats in Tokyo.

AmidperiodicreviewsofthenuclearoptioninJapan,nationalpolicyhas consistently depended on the “full range” of U.S. military might to deter nuclearattacks.Thispolicyhasbeenaccompaniedbyfrequentreminderstonuclear-armedrivals,aswellastoWashington,thatpreemptivestrikesandtheuseofnuclearweaponscanbevalidformsofself-defense.Japanhasmadeitclearsincethe1950sthatitreservestheright(andwillmaintainthecapacity)todevelopanucleararsenalofitsown.Thisstrategy—“lyingbetweennuclearpursuitandnuclearrollback”—istheessenceof“themostsalientexampleofnuclearhedging”amongglobalpowers.3 One Japanese analysthasframedJapan’spositiononnuclearweaponsasabalancingactbetweennuclearapprovalandnucleardenial.4

Over the past four decades, Japan has maintained viable—andunconcealed—optionsfortherelativelyrapidacquisitionofnuclearweaponsandhasjustifieditsdecisionnottopursuenuclearbreakoutinmanyways.Buteachtimetheregionalsecurityenvironmenthasshifted—suchasafterChina’sfirstnucleartestin1964,theendoftheColdWar,NorthKorea’snuclear

2 “JapanRefusestoBackStatementagainstA-bombs,”Japan Times,April26,2013. 3ThisconceptisintroducedanddevelopedinArielE.Levite,“NeverSayNeverAgain:Nuclear

ReversalRevisited,”International Security27,no.3(2002/3):59–88,59,71.MikeM.Mochizukicalls it “pragmatic pacifism” and argues that “it made sense [for Japan] to retain at least a latent capabilitytoexercisethenuclearoption.”SeeMikeM.Mochizuki,“JapanTeststheNuclearTaboo,”Nonproliferation Review14,no.2(2007):311.LlewelynHughesrejectstheterm“nuclearhedging”butacknowledgesthat“thedoortoindependentnuclearization[byJapan]remainsajar”andthat“formalbarrierstonuclearizationaresurmountable.”SeeLlewelynHughes,“WhyJapanWillNotGoNuclear(Yet):InternationalandDomesticConstraintsontheNuclearizationofJapan,”International Security31,no.4(2007):67–96,69,91.

4 YuriKase,“TheCostsandBenefitsofJapan’sNuclearization:AnInsightintothe1968/70InternalReport,”Nonproliferation Review 8,no.2(2001):55.

SamuelsandSchoff – Japan • 235

breakoutinthe2000s,orthe2010U.S.-RussiaNewStrategicArmsReductionTreaty(START)agreementlimitingwarheadsandlaunchers—Tokyohasre-examineditspolicybeforesignalingfor(andaccepting)U.S.reassuranceon extended deterrence.

Earlyon,U.S.reassuranceswereastraightforwardmatter.Inthe1960s,U.S.nuclearweaponsweredispersedwidelyaroundtheworld.Inadditionto thousands of nuclear-tipped missiles back home and patrolling the seas, theUnitedStateskeptnearly3,000nuclearweapons “on shore” in theAsia-Pacific,includingsome1,200inOkinawa,whereU.S.strategicbomberswerebased.5ThisnucleardeterrentcostJapanrelativelylittle:hostingU.S.militarybasesandprovidingforitsownbasicdefense.ThecombinationofJapan’sunwillingnesstocontributefullytoitsowndefenseortothedefenseof its U.S. ally and Japanese expressions of concern about the reliability of the U.S. nuclear umbrella accentuated Japan’s cheap ride on national security.6

ReassuringJapanismorechallengingtoday,however,andhowTokyosortsthroughitsstrategicchoicesismorepertinentthanever.Japanfacesnewnuclearthreatsandrelativeshiftsintheregionalbalanceofpower.Althoughmoreaccurateandmorepotent,theU.S.nucleararsenalisnowsmallerandless visible, and the “second nuclear age” is ushering in a multipolar and less predictable nuclear landscape.7TheUnitedStateswithdrewthelastofitsland-basednuclearweaponsfromAsiain1991andreduceditsoverallnuclearstockpilebyabout75%sincethen,withfurtherreductionsbeingconsidered.8Morerecently,U.S.reassurancehasfocusedonthecapabilityandflexibilityofspecificsystems,butthishasbeenundercutbyWashington’sretirementofsomethatwereearliertoutedasbeingmission-critical.9 Bilateral dialogue and closer policy coordination have become more important aspects

5 RobertS.Norris,WilliamM.Arkin,andWilliamBurr,“WhereTheyWere:HowMuchDidJapanKnow?”Bulletin of the Atomic Scientists56,no.1(1999):30.OkinawawasunderU.S.administrativecontrol at the time.

6 OnU.S.concernsaboutaJapanesenuclearbreakoutinthe1960s,seeFrancisJ.Gavin,Nuclear Statecraft: History and Strategy in America’s Atomic Age(Ithaca:CornellUniversityPress,2012).ForananalysisofJapan’s“cheapride,”seeRichardJ.Samuels,Securing Japan: Tokyo’s Grand Strategy and the Future of East Asia,(Ithaca:CornellUniversityPress,2007).Ontheconnectionbetweenextendeddeterrenceandthe“irony”oftheimbalancedcommitmentstothealliance,seeBarryR.Posen,U.S. Grand Strategy: The Case for Restraint(Ithaca:CornellUniversityPress,forthcoming).

7 KeithB.Payne,Deterrence in the Second Nuclear Age (Lexington:UniversityPressofKentucky,1996). 8 “FactSheet:IncreasingTransparencyintheU.S.NuclearWeaponsStockpile,”U.S.Department

ofDefense,May3,2010,http://www.defense.gov/npr/docs/10-05-03_fact_sheet_us_nuclear_transparency__final_w_date.pdf;andScottWilson,“Obama,inBerlin,CallsforU.S.,RussiatoCutNuclearWarheads,”Washington Post,June19,2013.

9 Forexample,theretirementofnuclear-tippedTomahawklandattackcruisemissiles(TLAM/N)wasannouncedin2010.SeeWadeL.Huntley,“SpeedBumpontheRoadtoGlobalZero:U.S.NuclearReductionsandExtendedDeterrenceinEastAsia,”Nonproliferation Review20,no.2(2013):311–12.


ofreassuranceanddeterrenceforthealliance,butthedegreetowhichthiscanmitigaterisingJapaneseconcernsaboutNorthKoreaandChinaisuncertain.

Japanesepublicopinionremainsstaunchlyanti-nuclear,andJapanwouldlikelybethelastcountryinNortheastAsiatooptfornucleararms.Butwhilethere are many domestic and international constraints on nuclear breakout, there are also signs of a more sophisticated debate in Japan about these issues asthedemandforreassurancehasescalated.ThekeyquestionsarehowJapanperceivesitsoptions,whetherandhowitscalculuscouldchange,andwhatthiswouldmeanfortheregionandtheU.S.-Japanalliance.

Toaddressthesequestions,thischapterexaminestheoriginsandcurrentstateofJapan’snuclearhedgeandconsidershowdeterrenceandreassurancedynamicsareevolvingintheregion.ItthenexplorestheprospectsandimplicationsforanuclearbreakoutbyJapan,aswellasalternativestrategicpaths that Japan and the alliance can take. Although Japan’s nuclear hedging strategyis likelytocontinueinthenearfuture,U.S.policymakers(andthosethroughouttheregion)shouldnotbesanguineaboutthisstrategycontinuingindefinitely.Japan’schoiceswillbedeterminedultimatelybyhowwellpotentialthreatscanbemanagedandbythestrengthoftheU.S.commitment to extended deterrence.

Japan’s Current Posture

Theevolutionof Japan’snuclearpostureowesasmuch topoliticalcircumstances as to a realistic assessment of U.S. capabilities and commitment. Japaneseleadershaveunderstoodthatthepursuitofnuclearweaponsispolitically, diplomatically, and economically impracticable, but they also recognize that an independent nuclear deterrent is unnecessary as long as U.S. guarantees remain credible to potential adversaries. As a result, Japan decidedearlyontodenyitselfnuclearweaponsandinsteadhedgeagainstchanging circumstances.

Japan’snuclearhedgehastwoelements.Thefirstinvolvesconfirming(andserially reconfirming) theU.S.commitmentandcapability tousenuclearweaponsindefenseofJapan.In1965,forexample,PrimeMinisterEisakuSatoaskedDefenseSecretaryRobertMcNamaratopledgetodeploynuclearweaponsagainstChinaintheeventofwar.McNamaraandPresidentLyndonJohnsongavethatassurance.Similarconversationshavefollowedatvariouslevelsofgovernmentandthemilitary,alwaysbackedbyreassuringpublicstatementsfromWashington.Inaddition,fordecadestheJapanesegovernment turned a blind eye to the possible introduction of U.S. ship- and aircraft-basednuclearweaponsduringportandbasevisitsinJapan,despite


its public pledge to forbid such practices.10Beginningin1976,eachofJapan’sNationalDefenseProgramOutlineshasstatedthatJapanwilldependonU.S.extended deterrence.

The second element involves Japan’s maintenance of the foundation foritsownnuclearweaponsprogram,shouldthecountryevermakethatchoice. Former primeminister Nobusuke Kishi believed that nuclearweaponswereabsolutelynecessaryifJapanweretohaveinfluenceinworldaffairs,andheinstructedhisCabinetLegislationBureauin1957toformallypronouncethatJapan’sconstitutionallowedthecountrytopossessnuclearweaponsforself-defense.11AnoriginalmemberofJapan’sAtomicEnergyCommissionrecalledhow“wewerepressuredrepeatedlytodobasicresearchonhowtomakeanatomicbomb.”12Leadingpoliticianshavereassertedtheconstitutionalityofnuclearweaponsthroughouttheyears,includingcurrentand former prime ministers Shinzo Abe and Taro Aso.13Inaddition,animportantpolicystudybyJapan’sMinistryofForeignAffairs(MOFA)notedin1969that“regardlessofjoiningtheNPTornot,wewillkeeptheeconomicandtechnicalpotentialfortheproductionofnuclearweapons,whileseeingtoitthatJapanwillnotbeinterferedwithinthisregard.”14

Towardthislatterend,anddespiteconsiderableoppositionfromwithinJapanandfromtheinternationalcommunity,Japanhasneverwaveredfromits early commitment to completing the nuclear fuel cycle. This commitment entails the maintenance of vigorous enrichment and reprocessing capabilities, the stockpiling of separated plutonium, and the development of a fast breeder reactor(FBR)thatothernations—mostprominentlytheUnitedStates—havelongsinceabandonedastoocostlyanddangerous.Infact,Japanhasthelargestnuclearpowerprogramofanynon-weaponsstateandistheonlyone

10 MartinFackler,“JapanSaysItAllowedU.S.NuclearShipstoPort,”New York Times,March9,2010;andNorris,Arkin,andBurr,“WhereTheyWere,”31.

11 Samuels, Securing Japan,176.KishiandthenforeignministerHisanoriYamadareportedlytoldGeneralMacArthurin1958thattheirgovernmentwasexploringthenuclearweaponsoption.See“JapanDiscussedAcquisitionof‘Defensive’NuclearWeaponsin1958,”Japan Times,March17,2013.

12 JacquesE.C.Hymans,“VetoPlayers,NuclearEnergy,andNonproliferation:DomesticInstitutionalBarriers to a Japanese Bomb,” International Security36,no.2(2011):167.

13 AbemadehiscommentinaspeechatWasedaUniversityinMay2002whenhewasdeputychiefcabinetsecretary,andAsomadethecommentinNovember2006whenhewasforeignminister.ThefirstAbeadministrationofficiallyclarifiedthisstanceina2006statementbeforetheDiet,sayingthat“evenwithnuclearweapons,we’veunderstoodthatpossessingthemwouldnotnecessarilyviolatetheconstitutionaslongasitiskeptwithin[thelimitsofminimumcapabilitiesnecessaryforself-defense].”See,forexample,“JapanCanHoldNuclearArmsforSelf-Defense:Govt.,”Reuters,November14,2006.

14 SeeTakaDaitoku,“TheKishiDoctrineandtheConstructionofaVirtualNuclearStateinPostwarJapan”(paperpresentedtotheAnnualMeetingoftheAmericanHistoricalAssociation,NewOrleans,January5,2013);andMainichi Daily News,August2,1994.


withfull-spectrumfuelcyclecapabilities.15Ofcourse,Japan’snuclearpowerindustrysufferedamajorblowafterthe2011tsunami-inducedmeltdownsatplantsinFukushima,andtherearemanylegal,political,andtechnicalrestrictionsthatwouldmakeaJapanesenuclearbreakoutextremelydifficult.Nonetheless,ithasalwaysbeenimportantforJapantokeepthatoptionopen.

Opening the Nuclear UmbrellaNestlingundertheU.S.“nuclearumbrella”wasneveruncontroversial.

Left-wingpoliticiansarguedinthemid-1960sthatthispolicywaspartofWashington’splanforglobaldomination,andmuchofthepublicfearedbecomingentangledinanuclearwarbetweensuperpowers.16 Some on the politicalright,seeingrelianceonU.S.nuclearweaponsasasymbolofJapan’ssecond-tierstatus,worriedaboutnationalprestigeandpushedforamoreovert hedge.17Conservativepoliticalleaders—includingShigeruYoshidaandHayatoIkedainthepragmaticwingoftheLiberalDemocraticParty(LDP)andrevisionistssuchasIchiroHatoyamaandYasuhiroNakasone—repeatedlycalled in private for an indigenous nuclear capability.18

Insidethebureaucracy,opinionsweremixed.MOFAwarnedin1959thatJapanshouldnotruleoutthepossibilityofdevelopingnuclearweapons,lestthe country lose flexibility in pursuing national security.19Later,in1966,aviceministerofforeignaffairsstatedpubliclythatJapanwasnotprotectedundertheU.S.nuclearumbrella.MOFAimmediatelyissueda“unifiedviewpoint,”introducingoneofmanyawkwardlocutionstheJapanesegovernmentusestodescribeitsnationalsecuritystrategy:itwasnotaccuratetosaythatJapanwasnotcoveredbythenuclearumbrella.20

Sato, initially a supporter of Japanese nuclear armament, reversed coursewhenconfrontedwithWashington’sstrongnonproliferationpolicy

15 NobumasaAkiyamaandKentaHorio,“CanJapanRemainCommittedtoNonproliferation?”Washington Quarterly36,no.2(2013):152.FormoreonthedomesticdisputesaboutJapan’s“nuclearbackend,”seeRichardJ.Samuels,3.11: Disaster and Change in Japan(Ithaca:CornellUniversityPress,2013).

16 Nikkan Joyaku nado Tokubetsu Iinkai: Nipponkoku to Dai Kan Minkoku to no aida no Kihon Kankei ni Kansuru Joyaku nado no Teiketsu ni tsuite Shonin wo Motomeru no Ken[ProceedingsoftheSpecialCommitteeConsideringtheProposedJapan-KoreaTreaty],HouseofCouncillors,TheNationalDietofJapan,December3,1965.

17 Daitoku,“KishiDoctrine,”2.18 SeeAyakoKusunoki,“TheSatoCabinetandtheMakingofJapan’sNon-NuclearPolicy,”Journal of

American–East Asian Relations15,nos.1–2(2008):28–29;andDaitoku,“KishiDoctrine,”3.19 “No-NukePolicyRuledOutYearsbeforeDeclaration,”Kyodo News, December22,2008. 20 NobumasaAkiyama,“TheSocio-PoliticalRootsofJapan’sNon-NuclearPosture,”inJapan’s Nuclear

Option: Security, Politics, and Policy in the 21st Century, ed.BenjaminSelfandJeffreyThompson(Washington,D.C.:HenryL.StimsonCenter),86.Forsimilarrhetoricalgymnasticsondefensepolicy, see Samuels, Securing Japan.


andhisowngovernment’s internal studiesconcluding that relianceonextendeddeterrencewasthebestwayforward.21Noneoftheconceivablealternatives—i.e.,domesticnuclearweaponsproduction,nuclearsharingwiththeUnitedStates,orovertlydenyingU.S.nuclearprotection—wasconsidered viable at that time by most Japanese strategists. Understanding this reality,andprovidedwithhigh-levelU.S.assurances,in1967Satoannouncedthreenon-nuclearprinciples:non-possession,non-manufacture,andnon-introduction.Ayearlaterhearticulatedthe“fourpillars”policy,andin1970thegovernmentsignedtheNPT,leavingnodoubtaboutJapan’srelianceonthe U.S. nuclear umbrella.22

One of the four pillars is the three non-nuclear principles, and this pillar isaccompaniedbythreemore:(1) promotingnuclearpowerforpeacefulpurposes,(2) promotingglobalnucleardisarmament,and(3) relyingontheU.S. nuclear deterrent for protection from the international nuclear threat. The four pillars policy officially opened the nuclear umbrella, and even if it is perceived as leaky by some, this umbrella has remained open ever since. Althoughheprivatelycalledthethreeprinciples“nonsense,”SatowasawardedtheNobelPeacePrizein1974.

Japan’s “Basic Defense” Rationale and Its Latent Nuclear Deterrent Aroundthistimeintheearly1970s,Japanesedefenseofficialsmoved

awayfromambitiousplansforarobustSelf-DefenseForce(SDF)andadjustedtothepoliticalandeconomicrealitiesofthetime.Abellwetherdocumentpennedin1971byTakuyaKubo,thedirectoroftheDefenseBureauoftheJapanDefenseAgency(JDA),outlinedanewdirectiontowardbasicdefense.Kubosaw“noprobablethreats”toJapanandrationalizedasmalldefenseestablishmentandclosealliancewiththeUnitedStates.23KuboagreedwithotherleadingstrategicthinkersthatnuclearweaponshadlimitedmilitaryutilityforJapan.Thecountrywastoodenseandtoosmallandwouldalways

21 Somesuggestthatitisalsopossiblethatratherthanseriouslyadvocatingfornuclearweapons,SatowasinsteadtakingthatpositioninordertoextractsecurityguaranteesfromWashington.SeeKusunoki,“SatoCabinet,”31;andMichaelJ.GreenandKatsuhisaFurukawa,“Japan:NewNuclearRealism,”inThe Long Shadow: Nuclear Weapons and Security in 21st Century Asia,ed.MuthiahAlagappa(Singapore:NationalUniversityofSingaporePress,2009),357.Othersarelesscertain.SeeKurtM.CampbellandTsuyoshiSunohara,“Japan:ThinkingtheUnthinkable,”inThe Nuclear Tipping Point: Why States Reconsider Their Nuclear Choices,ed.KurtM.Campbell,RobertJ.Einhorn,andMitchellB.Reiss(Washington,D.C.:BrookingsInstitutionPress,2004),218–53;andEtelSolingen,Nuclear Logics: Contrasting Paths in East Asia and the Middle East (Princeton:PrincetonUniversityPress,2007),73.

22 FormoreontheSatoturnaround,thethreeprinciples,andthefourpillars,seeGreenandFurukawa,“Japan:NewNuclearRealism”;Kusunoki,“SatoCabinet”;andSolingen,Nuclear Logics.

23 Kubo’smemowastitled“AFrameworktoConsidertheArrangementofJapan’sDefenseCapabilities,”availableatWorldandJapandatabase,UniversityofTokyoInstituteofOrientalCulture,February20,1971,http://www.ioc.u-tokyo.ac.jp/~worldjpn/documents/texts/JPSC/19710220.O1J.html.


losemorethanitgainedinanuclearexchange.Moreover,adversarieswereunlikelytobelievethatJapanwouldactuallyuseitsnuclearweapons—alackofcredibilitythat,accordingtoKubo,underminedtheirdeterrenteffect.“There is no choice but to rely on U.S. extended deterrence,” he concluded.24

Japan’s basic defense concept became the centerpiece of the country’s first NationalDefenseProgramOutlinein1976andcontinuedtoshapeJapan’sdefensestrategyuntilitwassupersededin2010 by a “dynamic defense” concept.25AlthoughforKubonuclearbreakoutwasoffthetable,hismemoclearly articulated Japan’s nuclear hedge, positioning the hedge more as a signaltoJapan’sU.S.allythantoitsadversaries:“[Japanshould]establishastructure to develop considerable nuclear armament capability at any time…[so]theUnitedStateswillgetworriedaboutunstableinternationalrelationsduetonuclearproliferationandwilldesiretomaintaintheU.S.-Japansecurityregime including extended deterrence.”26

ThemostprominentandcredibleelementofJapan’slatentweaponscapability is its sophisticated nuclear energy program and, in particular, its decades-long national commitment to completing the nuclear fuel cycle in thenameofenergyindependence.Thisgoaljustifiesreprocessingspentfueland accumulating separated plutonium for use in a “pluthermal” mixed-oxide (MOX)product.ExtractingmoreenergyfromspentfuelbyreusingitandoperatingFBRsthatproducemorefissilematerialthantheyconsumecanreleaseJapanfromitsdependenceonimportedfuels.Intheory,thisenergystrategy sounds sensible.Theproblem,however, is that the economicsandengineeringbehindthisMOX/FBRstrategyarenotworking,andtheplutonium continues to accumulate.27Japan’sstocksofplutoniumnowvastlyoutweightheamountneededforanyplausiblenuclearpowerornuclear

24 Kubo,“AFrameworktoConsidertheArrangementofJapan’sDefenseCapabilities.”25 See “Summary of National Defense ProgramGuidelines for FY 2011 and Beyond,” Japan

Cabinet Secretariat, 3, http://www.kantei.go.jp/foreign/policy/decisions/2010/__icsFiles/afieldfile/2012/01/27/summary_ndpg_e.pdf.

26 Kubo,“AFrameworktoConsidertheArrangementofJapan’sDefenseCapabilities.”27 See“TheCurrentSituationofPlutoniumManagementinJapan,”AtomicEnergyCommissionof

Japan,September20,2011,http://www.aec.go.jp/jicst/NC/iinkai/teirei/siryo2011/siryo36/110920e.pdf.Attheendof2011,Japanhad44.3 metrictonsofseparatedreactor-gradeplutonium.Ofthis,9.3 metrictonsareinJapan.Theremaining35 metrictonsareinreprocessingplantsinFrance(LaHague)andtheUnitedKingdom(Sellafield).See“CommunicationReceivedfromJapanConcerningItsPoliciesRegardingtheManagementofPlutonium,”InternationalAtomicEnergyAgency(IAEA),October3,2012,http://www.iaea.org/Publications/Documents/Infcircs/2012/infcirc549a1-15.pdf.


weaponsprogram.OneleadingAmericanexpertsuggeststhattodaythereis“enoughplutoniuminJapantomake1,000nuclearweapons.”28

Japan’snuclearhedgerequiresthattheconnectionbetweennuclearpowerandnucleararmsnotbehidden.WhentheJapanesenuclearpowerindustryfacedeliminationaftertheMarch2011catastropheinnortheasternJapan,seniorleaders—includingSatoshiMorimoto,theincumbentdefenseministerin2012—arguedthatnuclearpowerwasthebasisfora“latentdeterrent”andmustbepreserved.Likewise,formerdefenseministerShigeruIshibasaidthatitwas“importanttomaintainourcommercialreactorsbecauseitwouldallowustoproduceanuclearwarheadinashortamountoftime.”29

A second element of Japan’s nuclear hedge is the expertise in potential weapon-deliveryplatformsthatthecountryhasgainedthroughitsspaceprogram.30Althoughitsprimaryspace-launchvehicle,theH-IIseries,ispoorlysuitedasamissile—givenitsliquid-fuelcomposition—Japanhasconsistentlypursuedsolid-fuelrockettechnology,startingwiththeKappain1956andeventuallyleadingtothe1.8-tonpayloadM-Vin1989.31 The decisiontodiscontinuetheM-Vin2006overcostconcernswasopposedbysomemembersoftheDietwhobelievedthegovernmentshouldmaintainsuch technology for its potential military utility.32TheM-V’ssuccessor,theEpsilon-1,willflyitsfirsttestin2013.

Although Japanese rockets are not designed to re-enter the atmosphere orhitaspecifictarget,theJapanAerospaceExplorationAgencyhasbeenexperimentingwithre-entrytechnologysinceatleast1994andaccomplisheditsfirstcontrolledre-entryfortheupperstageoftheH-IIBrocketin2011.33 Japan has had access to U.S. ballistic missile defense technologies at both the upper(mid-course)andlower(terminalphase)tiers,andhasbeendeveloping

28 FrankvonHippel,“ShouldtheU.S.EncourageSouthKoreaandJapantoMakePlutonium-basedNuclearFuels?”(presentationattheNonproliferationPolicyEducationCenter,Washington,D.C.,April4,2013).IchiroOzawa,aseniorJapanesepolitician,hassuggestedthatthenumberofpotentialwarheadsisclosertothreeorfourtimesvonHippel’sestimate.Adecadeago,JeffreyW.ThompsonandBenjaminL.SelfestimatedthatnumbertobeinthehundredsinJapan’s Nuclear Option,163.

29 Samuels, 3.11: Disaster and Change,124.Fortheirpart,AmericanofficialsrushedtosupportthebeleagueredJapanesenuclearpowerprogramafterthedisastersofMarch11,2011.SomereportthatthiswasduetoU.S.concernsabouttheeffectofashutdownonexcessiveplutoniumstockpiles,butotherssuggestthatU.S.dependenceonJapanesenucleartechnologyrequiresarobustnuclearpowerindustry.AuthorinterviewwithaformerseniorJapaneseintelligenceofficial,Tokyo,March26,2013.

30 ForanoptimisticassessmentofthemilitarycapabilitiesofJapan’sspaceprogram,seeSaadiaM.PekkanenandPaulKallender-Umezu,In Defense of Japan: From the Market to the Military in Space Policy(Stanford:StanfordUniversityPress,2010);andforanopposingview,seeThompsonandSelf,“NuclearEnergy.”

31 KatsuhisaFurukawa,“MakingSenseofJapan’sNuclearPolicy:ArmsControl,ExtendedDeterrence,andtheNuclearOption,”inSelfandThompson,Japan’s Nuclear Option,114.

32 AuthorinterviewwithaJapanesedefenseanalyst,February8,2008.33 See“SuccessfulExecutionofControlledRe-entryofLaunchVehicleUpperStage,”JAXA Today,

August2012,22–23.


spacetechnologiestoassistwithprecisiontargeting,includinghigh-precisiontime control and orbital estimation.34

Studies of Japan’s nuclear options do not agree on how quicklythe country could establish a robust, survivable, independent nuclear deterrent—amuchmorechallengingtaskthanbuildingafewbombs.SomeconcludethatJapanistechnicallycapableofdevelopinganuclearweaponwithinayear(somestudiesevensuggestsixmonthsor less),whereasothersarguethatitwouldtakeatleastadecade.35ItiswidelyacknowledgedthatJapanlacksexpertiseonbombandwarheaddesign,reliabledeliveryvehicles, intelligence and counterintelligence capabilities designed to protect and hide assets from a potential first strike, a comprehensive command-and-controlsystem,andinfrastructuretosafelytestweapons.36 These are nottrivialconstraintsthatcouldbeovercomeimmediately.Forexample,if Japanwanted a sea-baseddeterrent—an attractiveoption given itsgreatersurvivability—itwouldhavetodevelopballisticmissilesubmarinesandpossiblynuclear-poweredones.Likewise,theuseofreactor-gradeplutonium,thoughnotimpossible(andnotlikelyJapan’sfirstchoice),wouldcreatenewdifficultiesandtakeadditionaltime.

Thereis,ofcourse,analternativeandmorelikelyroute—usinghighlyenricheduranium(HEU).ThecontroversialRokkashonuclearenrichmentplanthassophisticatedcentrifuges thatprovide Japanwithauranium-enrichmentcapability.Another,lesslikelypathtoproducingweapons-gradeHEUcouldbethroughaprocessoflaserisotopeseparation,whichJapandabbled in for years before inefficiencies led to a cutback on implementation plans in 2001. Although laser enrichment is not commercially attractive, the know-howandequipmentremaininJapan,andaswelearnedinthecaseof

34 PekkanenandKallender-Umezu,In Defense of Japan, 36–37;andNarushigeMichishita,“Japan’sResponsetoNuclearNorthKorea,”Joint U.S.-Korea Academic Studies23(2012):99–112.

35 These comparisons are imperfect. Some refer to building a single bomb, others to building a robust, survivablearsenal.Forarangeofestimates,seeFederationofAmericanScientists,“Japan’sNuclearWeaponsProgram,”April16,2000,http://www.fas.org/nuke/guide/japan/nuke;MatakeKamiya,“NuclearJapan:OxymoronorComingSoon?”Washington Quarterly 26,no.1(2002–3):63–75;ToshiYoshiharaandJamesR.Holms,eds.,Strategy in the Second Nuclear Age: Power, Ambition, and the Ultimate Weapon(Washington,D.C.:GeorgetownUniversityPress,2012);Kusunoki,“TheSatoCabinet”;andNationalIntelligenceEstimate,“TheLikelihoodofFurtherNuclearProliferation,”no.4-66,January20,1966,availablefromGeorgeWashingtonUniversity’sNationalSecurityArchive,ElectronicBriefingBook,no.155,June1,2005,http://www.gwu.edu/~nsarchiv/NSAEBB/NSAEBB155/prolif-12.pdf.Asecretgovernment-requestedstudyin2006estimatedthatitwouldtake“atleast3to5yearsuntilJapancangointotrialproductionofaminiaturizedwarhead.”SeeSankei Shimbun,December25,2006.

36 SeeJeffreyLewis,“HowLongforJapantoBuildaDeterrent?”ArmsControlWonk,weblog,December28,2006,“http://lewis.armscontrolwonk.com/archive/1339/japans-nuclear-status;andHajimeIzumiandKatsuhisaFurukawa,“NotGoingNuclear:Japan’sResponsetoNorthKorea’sNuclearTest,”Arms Control Today37,no.5(2007),http://www.armscontrol.org/act/2007_06/coverstory.


SouthKoreain2004,experimentstoproduceHEUinsmalldosescanbedifficultforIAEAinspectorstodetect.37

ThereareotherskillsinwhichJapaneseresearchersexcelthatareoftenneglected in discussions of Japan’s latent deterrent. These include high-speed framing radiography, heavy-metal shock physics, radiation hydrodynamics, andexplosiveshaping.Knowledgeintheseareasandothersthatarebasicfor development of a thermonuclear device is scattered throughout Japan’s industrialandresearchcommunities.ItisnotuncommonforJapaneseresearch scientists to attend and present papers on shock compression or high-speed photonics at international conferences also attended by nuclear weaponsscientists fromtheUnitedStates,Russia,andChina.38 These research activities have practicalapplicationinawiderangeofnon-militaryareasandarenotnecessarilytelltalesignsofasecretnuclearweaponsresearchprogram.Indeed,whilesomepolicymakersinTokyowouldliketofosterclosertiesbetweenJapan’sscientistsanddefenseplanners,awidegulfremainsbetweenthetwocommunities.39ItalsoappearsthatJapanlacksdeepexperiencewithotheractivitiesrelevanttoaweaponsprogramsuchasplutoniummetallurgyorberylliummachining,whichcouldbehelpfuldependingonwhatpathitchooses.

Still, Japan clearly has mature capabilities in certain areas, capabilities that are as relevant to its nuclear hedge as the country’s plutonium stockpile. Itisalsoevidentthatnationalpolicyrecognizesthevalueoftheseprogramsin preventing both the United States and potential adversaries from taking Japan’s non-nuclear status for granted. In short, given Japan’s level oftechnological sophistication, stable civil-military relations, accessible and plentiful plutonium stockpiles, self-contained nuclear fuel cycle, and history of success in “spinning on” commercial technologies, the country’s nuclear hedge remains intact and credible.40

37 In2004,SouthKoreanofficialsadmittedtotheIAEAthatgovernmentscientistsconductedHEUexperimentsin2000(withoutauthorization)usinglaserisotopeseparation,successfullyproducingsmallamountsofnearlyweapons-gradeuranium.

38 ForamoredetailedassessmentofJapan’stechnicalandscientificcapacitytoproducenuclearweapons,seeJamesL.Schoff,“RealigningPriorities:TheU.S.-JapanAllianceandtheFutureofExtendedDeterrence,”InstituteforForeignPolicyAnalysis,March2009,44–49,http://www.ifpa.org/pdf/RealignPriorities.pdf.

39 KatsuhisaFurukawa,“Japan’sPolicyandViewsonNuclearWeapon:AHistoricalPerspective,”Jebat: Malaysian Journal of History, Politics, & Strategic Studies37(2010):21–22.

40TheU.S.DepartmentofEnergyreportsthatreactor-gradeplutoniumcouldbeusedtoproducereliableweaponscomparabletothoseproducedusingweapons-gradeplutonium.SeeMarvinMiller,“Japan,NuclearWeapons,andReactor-GradePlutonium”(paperpresentedtoaseminarattheNuclearControlInstitute,Washington,D.C.,March27,2002),http://www.nci.org/02NCI/04/mm-jpu-paper.htm.ForahistoryofJapan’stechnological“spinon”fromcommercialtomilitaryapplications, seeRichard J. Samuels, “Rich Nation, Strong Army”: National Security and the Technological Transformation of Japan(Ithaca:CornellUniversityPress,1994).


Extended Deterrence 2.0

The U.S.-Japan alliance and its extended deterrent have enabled the nonproliferation policies that help Tokyo signal its intention to refrain frombreakingoutwithitsownnucleararsenal.AnothervitalfactorhasbeentheabsenceofaconsistentexistentialthreattoJapan.Wheneveroneorbothofthesefactorsseemstoshift,signsofreconsiderationinTokyobecome apparent and subtle reminders that Japan has other nuclear options areissuedtoWashington.JapanhaslongunderstoodhowimportantthenonproliferationobjectiveistotheUnitedStates,andhowtouseitforpolicy leverage.41

The Primacy of ReassuranceJapanesepolicymakersoftenremindtheirU.S.andregionalcounterparts

(bothprivatelyandpublicly)abouttheimportanceoftheU.S.nuclearumbrellaandJapan’sownabilitytogonuclearifnecessary.Aswehavenoted,thenprimeministerSatomadesuchastatementin1964and1965,asdidformerprimeministerMorihiroHosokawain1998,oppositionleaderIchiroOzawainBeijingin2002,andthenforeignministerAsoafterNorthKorea’s2006nucleartest.42 AdditionalsignalshavebeensentthroughDietinterpellations,aswellasthrough unofficial channels and provocative political commentary.43

Washington’sresponsetothesesignalshasbeenconsistent.In2006,thenU.S.secretaryofstateCondoleezzaRicevisitedJapanandreaffirmedtheUnitedStates’“willandcapability”tomeetthe“fullrangeofitsdeterrenceandsecuritycommitments”inanattempttoreassureJapanthatitisstillwellprotected under the U.S. nuclear umbrella.44PresidentBarackObamaofferedsimilarpublicassurancesafterNorthKorea’ssubsequenttestsin2009and

41 SeeGreenandFurukawa,“Japan:NewNuclearRealism.”SeealsoStevenPifer,RichardC.Bush,VandaFelbab-Brown,MartinS.Indyk,MichaelO’Hanlon,andKennethM.Pollack,“U.S.NuclearandExtendedDeterrence:ConsiderationsandChallenges,”Arms Control Series,no.3,June2010.

42OnecouldalsospeculatethatJapan’sDecember2008declassificationoftheSato-McNamaranoteswasanothersubtlereminder,comingasitdidontheheelsoftheU.S.delistingofNorthKoreaasastatesponsorofterrorism,despitethelackofprogressonverifyingNorthKoreandenuclearization promises.

43 Althoughtherewerenomentionsof“extendeddeterrence”inDiethearingsin2008,therewere68in2009and58in2010.Seehttp://kokkai.ndl.go.jp.Thereisalsoalonghistoryofcommentsby“autonomists”outsidegovernment,suchasIkutaroShimizu,NishihachiHyodo,TadaeTakubo,andTerumasaNakanishi,whohavepressedJapantobreakawayfromU.S.securityguaranteesanddevelopitsownnucleararsenal.SeeKamiya,“NuclearJapan,”66–67;andFurukawaKatsuhisa,“MakingSenseofJapan’sNuclearPolicy:ArmsControl,ExtendedDeterrence,andtheNuclearOption,” in Self and Thompson, Japan’s Nuclear Option, 111.

44 “RemarkswithJapaneseForeignMinisterTaroAsoafterTheirMeeting,”U.S.DepartmentofState,October18,2006.


2013whenPrimeMinisterAbeaskedhimtoreconfirmtheU.S.commitmenttodefendJapanwith“anunshakeablenuclearumbrella.”45

For now, reliance on U.S. extended deterrence persists even ifdiscomfortwiththestatusquoisgrowing.Thisdiscomfortstemsfromdifferentsources.SomeJapanesepoliticiansandanalystsareworriedthatapolicydesignedforabipolarworldorderwillbecomelessreliableinamultipolarenvironmentfilledwithregionalnuclearpowers.Japancould,inthis formulation, become “detached” from U.S. strategic thinking.46WhilesomeseektopreventthisthroughclosertieswithWashington,otherschafeunderthepostwarlegalanddiplomaticrestraintsthatJapanagreedtolivewithforthesakeofeconomicdevelopment;theywouldpursueadifferentpostwarrelationshipwiththeUnitedStatesbytakingmoresecurityanddiplomaticmattersintotheirownhands.

Yet the Japanese express concern about extended deterrence incontradictoryways.WhereasoncetheyworriedabouttheU.S.commitmentwhenNorthKoreannuclearweapons couldnot reach the continentalUnitedStates—i.e.,thatWashingtonmightprioritizeproliferationoverthemedium-rangemissilethreat—nowthattheprospecthasbecomemorerealistic,theyexpressconcernsbecauseNorthKorea’snuclearweaponscouldtargettheU.S.homeland.Forexample,aSankei Shimbun editorial suggested thatWashingtoncouldbe“intimidated,”quotingaformerdefenseministryofficialwhoopinedthat“wecannotcompletelyruleoutthepossibilityofJapan’sbeingcutofffromU.S.nuclearstrategy.”47

In the case ofChina, the allies’ superiority in conventional forcesappearsmoreimportantthanthenuclearbalancefornow,especiallyastheU.S. arsenal shrinks. This comes in part from a core challenge of extended deterrence,whereinadeterrenceproviderseekstolimitaconflicttotheregionitisprotectinginordertoavoidanall-outwarthatmightentangleitshomeland.Basedonthislogic,whileWashingtonwilldoeverythingitcantopreventtheescalationorexpansionofanEastAsianregionalconflict,iftheU.S.militarycannotdominateconventionally,Washingtonmightdefaulttoaccommodationratherthanresorttonuclearweapons.Asoneformerdiplomat explained, “the conventional superiority advantage is critical, becauseitobviatesthewholedebateaboutwhetherornotWashingtonwould‘sacrificeLosAngelestosaveTokyo’inanuclearexchange.”48Consequently,even thoughnuclearweaponsareamajorpsychologicalcomponentof

45 Sankei Shimbun, February22,2013.46 YukioSatoh,“AgendaforJapan-U.S.StrategicConsultations”(articleadaptedfromapresentation

madeattheInternationalSymposiumonSecurityAffairs,Tokyo,November18,2009).47 Sankei Shimbun, February22,2013.48 AuthorinterviewwithaformerMOFAofficial,August1,2007.


extendeddeterrence(andcertainlythemosttalkedabout),JapanisalsofocusedontheU.S.projectionofconventionalpower,whichisunderstrainfromU.S. budget politics,Chinesemilitary developments, and Japan’sunwillingnesstoinvestinitsowndefense.

TheUnitedStates’budgetproblems,coupledwithitseffortstoreducenuclearweaponsglobally,exacerbateaconcernsomehaveinJapanoverthelong-term durability of the U.S. nuclear infrastructure. By some measures, U.S. nuclear capabilities have atrophied over time. The United States has not developedanewwarheadinover25years,andithasnottestedaweaponsince1992.TheU.S.DepartmentsofDefenseandEnergystatedin2008thattheUnitedStates“isnowtheonlynuclearweaponsstatepartytotheNPTthatdoesnothavetheabilitytoproduceanewnuclearwarhead.”49 The Obama administration is making some investments to upgrade existing nuclear infrastructure,butWashingtonwillsoonfacetoughandexpensivechoicesaboutwhatkindofnucleardeterrenttheUnitedStates(anditsallies)shouldhave in the future.

SomeU.S.defenseplannersbelievethatwhenmodernsecurityproblemsare pushed to the higher rungs of a conflict-escalation ladder, the nuclear arsenalinheritedfromtheColdWarwillprovetobeinappropriateforusesbeyond deterring a large-scale nuclear attack against the United States or a closeally.AsformerdeputysecretaryofdefenseJohnHamreobserved,“theColdWarleftuswithamassiveinventoryof[nuclear]weaponswenolongerneed…[and] a shrinking community of nuclear experts hold on [to it] as a security blanket for a future they cannot define.”50

RecentU.S.administrationshavebelieved thatdeterrence throughconventionalweaponsisdecisivelymorecrediblethandeterrencethroughanyexistingnuclearalternative.Thechallenge,however,isthatcontinuedU.S.investmentinconventionalmilitarysuperiorityispreciselywhatdrivesweakerstatestopursueasymmetricsolutionswithnuclearweapons(e.g.,NorthKoreaandIran)andpromptsothermajorpowerstokeeppacewiththeirownmilitaryinvestments(e.g.,China),furtherworryingregionalallieslike Japan. There is no easy balance that truly guarantees security through strengthwithoutfeedingintoabroadersecuritydilemma.

Giventherisingprofileofthesechallengessince2001,theUnitedStatesandJapanbeganbilateralconsultationsin2009onstrategicissuesraisedby

49 “NationalSecurityandNuclearWeaponsinthe21stCentury,”U.S.DepartmentofEnergyandU.S.DepartmentofDefense,September2008(emphasisintheoriginal).SomearguethatsincetheUnitedStateshasnoneedtodevelopanewwarheador,giventhesizeofitsdatabase,totestone,theterm“atrophied”ishyperbolic.OthershighlightU.S.investmentsinexpensivetestingtools—suchastheNationalIgnitionFacility—thatbolstertheUnitedStates’confidenceinthereliabilityofitsarsenal.Authors’personalcommunicationwithVipinNarang,June9,2013,andJamesActon,July8,2013.

50 JohnJ.Hamre,“TowardaNuclearStrategy,”Washington Post,May2,2005.


theimpendingU.S.NuclearPostureReview(NPR)andQuadrennialDefenseReview(QDR).Forthefirsttime,Japanmovedontothepathofofficiallydiscussing and even influencing U.S. nuclear strategy and force planning, somethingtowhichtheUnitedStates’NATOpartnershadlongbecomeaccustomed.JapanhadbeenunsettledbypriorNPRsthatunilaterallyshiftedtheU.S.forceposturewithlittleconsultation.51ItwasconcernedthattheUnitedStatesmightreachadecisiontoaccommodateNorthKorea,movetowarda“nofirstuse”policyonnucleararms,orretirenuclearweaponssystems,particularly thenuclearTomahawkcruisemissile (TLAM/N),withoutdeployingcompensatingcapabilities.52

During this time, Japanese officials reportedly gave Americaninterlocutors a “non-paper” that described key criteria for sustaining extendeddeterrence.Thepaperhighlightedreliability(i.e.,confidencethatwarheadswillfunctionproperly),flexibility(holdingdifferenttargetsatrisk),responsiveness,discrimination(keepinglow-yieldoptions),andtheabilitytobeeitherstealthyorvisible,aswarrantedbythesituation.53 WhiletherewassomedoubtatthetimeabouthowhighupthispaperhadbeenapprovedwithintheJapanesegovernment,aspectsofthesecriteriacontinue to be raised by Japanese officials, and the continuation of bilateral consultations on extended deterrence suggests that the allies have plenty to discuss.54ThesecriteriaappeartoreflectrealconcernsinJapanthatrequirecontinued alliance attention.

ThesuccessofthebilateralNPRconsultationsledbothsidestowanttocontinuetalks,andinMarch2011they“regularized”theExtendedDeterrenceDialogue(EDD).TheEDDisnowabiannualevent,withoneofthemeetingsofteninvolvingavisittoadeterrence-infrastructuresite.In2013,forexample,thisincludedatourofNavalBaseKitsapinWashingtonStatetoseethesubmarine leg of the nuclear triad and Trident missile facilities.55 These discussions are not trivial conversations or mere photo opportunities. They

51 Forsimilarreasons,theUnitedStatesinitiatedadialoguewithSouthKoreaataroundthesametime.52 ForJapaneseconcernsabout“nofirstuse,”seeSatoh,“Agenda”;andYukioSatoh,“Kakugunshuku

jidainoNihonnoanzenhosho”[JapaneseNationalSecurityinanAgeofNuclearArmsReduction],Gaiko Forum (2009):46–49.ForconcernsabouttheTLAM/N,seeHansM.Kristensen,“U.S.NavyInstructionConfirmsRetirementofNuclearTomahawkCruiseMissile,”FASStrategicSecurityBlog,weblog,March18,2013,http://blogs.fas.org/security/2013/03/tomahawk.

53 HansM.Kristensen,“Japan’sNuclearSecrets,”Sekai, October2009,http://www.fas.org/programs/ssp/nukes/publications1/Sekai2009.pdf.

54 Forsuggestionsthatthesecriteriaarenotrepresentativeofgovernmentorcitizenviews,seeGregoryKulacki,“JapanandAmerica’sNuclearPosture,”UnionofConcernedScientists,March2010,http://www.ucsusa.org/assets/documents/nwgs/japan-american-nuclear-posture.pdf.Japaneseofficialsmentionedthesecriteriainnumerousauthorinterviewsbetween2010and2013.

55 KevinBaron,“U.S.,JapanMettoTalkNuclearDeterrence,”ForeignPolicy,E-Ring,weblog,April12,2013,http://e-ring.foreignpolicy.com/posts/2013/04/12/us_japan_met_to_talk_nuclear_deterrence.


areajointexplorationbyknowledgeableofficialsofcurrentandemergingnuclearthreatstothealliance,alongwithpossibledeterrencestrategies.56

The site visits are thorough and underscore the fact that U.S. declaratory statementsarebackedbydemonstrablecapabilities,withthehumancapitalbeing among the most important. Site visits make the U.S. nuclear umbrella visible and tangible for Japanese officials, and they highlight the significant investments that support it. Both countries’ principals hope that, over time, theEDDwillalsoenhancedeterrencebybetterintegratingnuclearandconventionalcapabilitieswithintheallianceforatailoreddeterrencestrategy,especiallyvis-à-visNorthKorea.TheEDDalsoprovidesJapanwithanofficialchanneltoshareitsperceptionsaboutextendeddeterrencewiththeUnitedStates,whichmakesthedialogueausefulbellwetherforhowtheJapanesegovernment feels about its nuclear hedge.

TheU.S.sidereportedlyispleasedthattheEDDhasdeepenedJapan’sunderstanding of extended deterrence and provided a better appreciation of the role played by conventional forces and missile defense, including high-end missile-tracking radar deployments in Japan.57 Still, the Japanese side appears to have an appetite for continued dialogue. Security planners in Tokyo acknowledgethatdiscussionsare“fardeeperthanbefore,”butsomeexpressconcernthatWashingtonwillcontinuetosurprisethem.58ReaffirmationofU.S.commitmentsandreliabilityaloneisnolongersufficient.TheEDDportends a more collaborative form of deterrence that encompasses the full spectrum of conventional and nuclear capabilities possessed by the allies. Japanesestrategistswhoonceexpressedlittlemorethan“sheerandtotaldependenceupontheAmericandeterrent”nowunderstandthatassuagingtheir abandonment fear requiresmore Japanese involvement in lower(conventional)thresholdsofpotentialconflict,andtheyseekgreaterinputintoWashington’snucleardoctrineandpriorities.TheEDDwillhavetobalance this carefully.59

56ThisinformationisbasedoninterviewswithparticipatingU.S.andJapaneseofficialsandmilitaryofficersinApril2013.ThetwosidesareledbyofficialsfromtheJapaneseForeignandDefenseMinistriesandtheU.S.StateandDefenseDepartmentsatthedeputydirectorgeneralanddeputyassistant secretary levels, respectively.

57 Huntley,“SpeedBumpontheRoadtoGlobalZero,”16,21.58 AuthorinterviewwithaseniordefenseplannerinJapan’sMinistryofDefense,Tokyo,March25,2013.59 PaulJ.Saunders,“ExtendedDeterrenceandSecurityinEastAsia:AU.S.-Japan-SouthKorea

Dialogue,”CenterfortheNationalInterest,January2012,http://www.cftni.org/2012-Extended-Deterence-In-East-Asia.pdf.


External ThreatsWhileWashingtonhassomecontrolinaddressingthereassurancefactor,

itfaceslimitswhenitcomestothreatsandthreatperceptions.NorthKoreaisaprimaryconcernforJapan,largelybecausePyongyangappearstocarelittleaboutitspeopleandinvestsheavilyinnuclearandmissileprograms.NorthKorea’snuclearcapabilitycouldmaketheleadershipevenmorereckless.Should the regime face imminent collapse or preemptive attack, it might judgethatithaslittletolose(andcouldevenforestalloutsideinterference)bystrikingJapanwithanuclearweapon.TherearealsoquestionsaboutwhetherPyongyangcanmaintaineffectivecommandandcontrolovertheseweapons.

Washington’sofficialassessmentsofNorthKorea’snuclearcapabilityarewrittenvaguelybutexpressconfidencethattheNorthwillbeabletoproducenuclear-tipped missiles in the not-too-distant future and that their accuracy willimprove.60TostrikeJapan,NorthKoreacouldusesomeofitsestimatedtwohundredNodongmedium-rangeballisticmissiles,whichhavearangeof1,500kilometersandapayloadofoneton.NorthKoreaisalsodevelopingaland-basedintermediate-rangemissile(Musudan)thatmightbeabletoreachOkinawaandGuam.Althoughtheaccuracyofthesemissileshasbeenderidedinthepast,abatteryoftestlaunchesinJuly2006suggestedthatNorthKoreahadimprovedtheirperformance,andinDecember2012itputa satellite into orbit for the first time using a three-stage rocket.61

A key problem for extended deterrence is the allies’ limited understanding ofPyongyang’sstrategiccalculusandWashington’sunexpressedpreferencetodealwithNorthKoreannuclearthreatsbyconventionalmethods.TherecouldcomeapointwhereJapaneseleadersfeelthattheyneedmorecontrolover themeansof response.A1995 JDAreportmade thispointwhileotherwisedismissingthevalueofanuclearoptionforJapan:“NorthKoreannuclearization…is not an issue that cannot be a condition for discussing the possibility of Japan going nuclear in the future.”62Inotherwords,theJDAidentifiedNorthKoreaasathreatthatcouldcauseJapantogonuclear.

ComparedwithNorthKorea,China’snucleararsenalandconventionalcapabilitiesaremuchlargerandweighheavilyonthemindsofJapanesedefenseplanners.ThemainworryisnotsimplythatChina’sdefensebudget

60 BradleyKlapperandLaraJakes,“NorthKoreaTensionPutsPressureonChina,U.S.,”Christian Science Monitor,April13,2013.Note,though,thatinaccuracycanbeanevengreaterthreat—forexample, if an adversary targets the Sea of Japan but hits an urban center.

61 YossefBodansky, “DPRKStrategicCommand andControl,Missile LaunchExerciseMarksOperationalWatershed,”Defense & Foreign Affairs Special Analysis 24,no.42(2006).

62 JapanDefenseAgency, “Concerning the Problemof the Proliferation ofWeapons ofMassDestruction,”1995,34,http://www.ucsusa.org/assets/documents/nwgs/1995jdastudy.pdf.


hasalmosttripledsince2001tobecometheworld’ssecondlargest.63Rather,itisthenatureofChina’smilitarymodernizationandtherelativelyquickand substantial investments in capabilities that are aimed at the allies’ abilitytodominatetheskiesandseasaroundEastAsia.ThisstrategicforcemodernizationraisesthepotentialcoststhatU.S.policymakerswouldneedtoweighwhenconsideringtheoptionofinterveningagainstChineseinterestsonbehalfofJapanorTaiwan.

Anotherlong-termproblemisthatChinakeepsbuildingnewnuclearwarheads(uptotenin2012).AlthoughofficialChinesepolicystatesthatChinawillnotusenuclearweaponsfirst—oreveragainstanon–nuclearweaponstate—itsintimidationtacticsinthemaritimeandcyberdomainshaveworriedsomeinJapanthatthesetacticscouldsomedayspreadtothenuclear realm.64ThePeople’sLiberationArmy(PLA),afterall,managesoneoftheworld’smostactiveballistic-missileprograms.Manyofitstacticalweaponshaveenhancedranges,accuracies,andpayloads,andsomeputOkinawawithinrangewhenforward-deployed.UpgradestoChinesemissilewarheads—includingmultipleindependentlytargetedre-entryvehicles—areenhancingBeijing’sdeterrentandstrategic-strikecapabilitiesvis-à-visJapanese and U.S. missile defenses.65Theseslow-movingupgradestothequality andquantity ofChinesenuclearweaponshave some inTokyowonderingwhetherBeijingwilleventuallyseeknuclearparitywiththeUnitedStates,somethingthatwouldrequireconsiderabletimeandinvestmentgiventhat the U.S. arsenal is significantly larger.

JapanesestrategistshavetoaskhowmuchvulnerabilitytheUnitedStatesiswillingtotolerateamidChina’sstrategicmodernizationandwhatitispreparedtodoonJapan’sbehalf,ifanything,inresponsetoChina’smoves.66 Some prominent Japanese analysts suggest that a national nuclear deterrent,evenifitwereinsufficienttodeteraforceasbigasChina’sinallcircumstances,couldcomplicatestrategiccalculationsinBeijingtotheextentthatChinawouldthinktwicebeforethreateningtouse(oractuallyusing)

63 U.S.officialsestimatethatChina’sactualdefensespendingwasroughly$60billionin2001andthatitcouldhavebeenashighas$215billionin2012.SeeOfficeoftheSecretaryofDefense,Annual Report to Congress: Military and Security Developments Involving the People’s Republic of China 2013 (Washington,D.C.,2013),45.

64 ForChina’swarhead increase, see thepress release for the2013 SIPRI Yearbook, Stockholm International Peace Research Institute (2013), June 3, 2013, http://www.sipri.org/media/pressreleases/2013/YBlaunch_2013.

65 OfficeoftheSecretaryofDefense,Annual Report to Congress: Military and Security Developments Involving the People’s Republic of China 2011(Washington,D.C.,2011),34.

66 BradRoberts,“NuclearMinimalism,”Arms Control Today 37,no.4(2007).


itsownnuclearforcesinaregionalcrisisorconflict.67Inshort,Japanfacesitsownthreatsandhasitsowninterests.AsKurtCampbellandTsuyoshiSunohara suggest, “the persistence of a Japanese-American alliance so robust thatitcanindefinitelypersuadeJapaneseleadersfromacquiringnuclearweaponscannotbeguaranteed.”68

Prospects and Implications for a Nuclear Weapons Breakout by Japan

Atthemoment,thelikelihoodthatJapanwouldbuilditsownnuclearweaponsislow.Constraintsaremultipleandsignificant.Buttheyarenotfixed,anditisworthwhiletoexaminetheconditions,bothinternalandexternal,underwhichtheseconstraintscouldloosenandJapanmightchange course.

Internal FactorsPublic opinion. The“nuclearallergy”metaphorwascoinedinpartto

describetheJapanesepublic’saversiontovisitsbyU.S.Navyvesselsthatmightbecarryingnuclearweapons.69JapaneseperceptionswerecolorednotonlybythebombsdroppedonHiroshimaandNagasakiin1945butalsobyotherincidents,suchasin1954whenaU.S.nucleartestatBikiniAtollexposed23Japanesefishermentohighlevelsofradiation,eventuallykillingoneandinspiring the Godzilla film series that sensationalized the potential danger andunpredictablenatureofnuclearweapons.70

ItwasagainstthisbackdropthatthenprimeministerSatoannouncedthe three non-nuclear principles, a policy that maintains strong public support.AstheColdWarwounddown,pollsshowedthatmorethan75%ofJapaneserespondentsstillagreedwiththethreeprinciples,andsimilarpollsin2006and2013producedthesameresult.A1998Galluppollfoundthatonly16%ofthenationwasafraidofbeingattackedbyanothercountryusingnuclearweaponsand89%feltnoneedforJapantohavenuclear

67 SeetheargumentsbyHisahikoOkazaki,“Mazugijutsutekinamenwotsumeyo”[First,WeNeedtoExaminetheTechnicalFeasibilityofaNuclearOption], Shokun!August2003;andGroupIchigaya,“KakubusonakiNipponniasuwanai”[ThereIsNoTomorrowforaJapanwithoutNuclearWeapons],Shokun!February2007.

68 CampbellandSunohara,“Japan:ThinkingtheUnthinkable,”237.69 GlennD.Hook,“TheNuclearizationofLanguage:NuclearAllergyasPoliticalMetaphor,”Journal

of Peace Research21,no.3(1984):259–75.70MichaelSchaller,Altered States: The United States and Japan since the Occupation (NewYork:Oxford

UniversityPress,1997):71–75.


weapons.71Beinganon–nuclearweaponsstatehad,itseemed,becomepartof Japanese national identity.72

TheriseofChinaandthebelligerencyofNorthKorea,however,haveraisedawarenessabouttheU.S.nuclearumbrella:onlyabout20%oftheJapanesepublicthoughttheumbrellawas“necessary”in1995,butalmosthalf thought so in 2010.73Still,evenwhencandidatesforthenationalDietwerepolledontheissueofJapandevelopingitsownnuclearweaponsaftertwoNorthKoreannucleartests,morethanhalfdidnotthinksuchanoptionshouldeverbeconsidered;onlyathirdfavoredkeepingthisoptionopenforthe future, depending on the international situation.74

The 2011 Fukushima nuclear accident hardened popular opinionagainstallthingsnuclearinJapanandledthegovernmenttoshutdownJapan’snuclearpowerinfrastructure.75Yetdespitepublicopinionandamoreindependent regulatory system, the current Abe administration and private industryarepushingtoreviveandsustainthenuclearsector.Withlittleorganizedpoliticaloppositiontotheconservative,business-friendlyLDPgovernment,wehaveseenJapan’snuclearindustrybegintoregainitsfooting.ItisalreadyaggressivelypursuingdevelopmentopportunitiesinAsia,Europe,andtheMiddleEast.

ThereturntopoweroftheLDPin2012isareminderthatoverwhelmingmajoritiescanvoteagainsttheirpolledpreferencesandthatevendemocraticgovernments can act independently of public opinion. The connection of publicopinion topolicymaking isparticularly tenuouswith respect tonationalsecurity.Forexample,therewasconsiderableoppositiontotheNPTfromthemedia,businesscommunity,andpublicwhenJapansignedthetreatyin1970.76Aswehaveseen,thedecisiontoforgoanindependentnucleararsenalwasbasedonrealistcalculationsamidU.S.pressure,notonpollingdata.CampbellandSunohara’sconclusioniscorrectthat“although

71 “Shitsumontokaito—Boeimondai,Asahi Shimbun seronchosashoho”[QuestionsandAnswersonDefenseIssues:ReportonAsahi Shimbun Opinion Survey], Asahi Shimbun, November6,1988;“Hikakusangensoku‘mamorubeki’8wari,‘kakuhoyugiron’wasanpinibun,Yomiuri Shimbun seronchosa”[80%WanttoKeeptheThreeNon-nuclearPrinciples:YomiuriOpinionPoll],Yomiuri Shimbun,November21,2006;“Asahi Shimbunshayusouseronchosa,shitsumontokaito”[QuestionsandAnswersforAsahi Mail-inSurvey],Asahi Shimbun,May2,2013;and“GallupJapanPollontheOwnershipofNuclearWeaponsandtheThreatofNuclearWar,”Gallup News Service, June5,1999.

72 Piferetal.,“U.S.NuclearandExtendedDeterrence,”33.73 “Towareruanpo,Nichibeikankei”[IssuesandtheU.S.-JapanAlliance],Asahi Shimbun,November

11,1995;and“Genbakutōkakara65nen,kienukakunokyoi”[65YearssincetheAtomicBombWasDropped,theNuclearThreatRemains],NHKReportingResearchandSurveys,October2010.

74 “Kurozuappu2012:Shuinsenkouhoshaanketo,hoshuseneikanojimin,kakubuso‘kentosubekida’38%”[Close-up2012:LowerHouseSurvey,38%SupportConsiderationofNuclearWeapons],Mainichi Shimbun,December8,2012.

75 See Samuels, 3.11: Disaster and Change, chap.5.76 GeorgeH.Quester,“JapanandtheNuclearNon-ProliferationTreaty,”Asian Survey 10,no.9(1970):766.


publicsentimentagainstnuclearweaponsremainsstrong,itsabilitytofullyinhibit the decisions of Japanese leaders should not be exaggerated.”77

Institutional opposition. Japanese political leaders considering nuclear breakoutwillfaceotherobstaclesbesidespublicopinion,includingoppositionfromanexpandingvarietyofpolitical,bureaucratic,andeconomicactors.Fordecades, bureaucratic responsibility for nuclear strategy resided solely in the Cabinet,withsupportfromMOFA.Overtime,however,theJDA—renamedtheMinistryofDefense(MOD)in2007—assumedagreaterpolicyrole.Nuclearpowerresearchanddevelopment,whichiscriticalforanypotentialdualuse,wassplitbetweentheMinistryofInternationalTradeandIndustry(MITI)—nowtheMinistryofEconomy,TradeandIndustry(METI)—andtheScienceandTechnologyAgency,whichisnowpartoftheMinistryofEducation.Eachministryhaditsownpreferences.78

Intheeconomicrealm,therearethosewhoseinterestslieinpreservingapurelycommercialexploitationofnuclearpower.79 Japan’s utilities, the widerbusinesscommunity,bureaucratschargedwithpromotingeconomicgrowth,andpoliticianswithtiestotheseinterestsareallpowerfulactorswhowouldlikelyopposeanuclearweaponsprogram.Intheeventofanuclearbreakout,Japan’selectric-powerindustrycouldbecrippledbyalossofaccesstonuclearfuelandwouldpossiblyberequiredtoreturncurrentfuelstocks,giventhattheirpurchasewaspredicatedonpeacefuluse.Moreover,largemanufacturerssuchasHitachiandMitsubishicouldbeshutoutofoverseasnuclear-developmentprojects,andtheremightbeawidereconomicbacklashagainstJapanesefirmsinkeymarketslikeChinaandSouthKorea,astheirgovernments hype the fear of a remilitarized Japan.80

Prefecturalgovernorsalsohaveanimportantvoteonwhatkindsofnuclear-relatedactivitiescanoccurwithintheirjurisdictions.Inaddition,some influential nonprofit organizations dedicated to preserving Japan’s non-nuclearstatusgainedstrengthfollowingtheFukushimacrisis.81ProponentsofchangingthenuclearstatusquoinJapanwouldlikelyfacenumerouslegalandbureaucratichurdles,includingthecertaintyofdrawn-outlegalchallenges.

Althoughthereisnoquestionthatweaponizationwouldbedifficultin Japan’s contested political system, circumstances can change over time.

77 CampbellandSunohara,“Japan:ThinkingtheUnthinkable,”242.SeealsoPaulMidford,Rethinking Japanese Public Opinion and Security(Stanford:StanfordUniversityPress,2011).

78 Accordingtoonestudy,eachpolicysiloacquiredanindependentvetoonnuclearbreakout.SeeHymans,“VetoPlayers.”

79 Hughes,“WhyJapanWillNotGoNuclear(Yet).”80 ForfurtheranalysisofhownuclearplantexportshavebeencentraltoJapan’s“newgrowthstrategy,”

see Samuels, 3.11: Disaster and Change. 81 Ibid.,chap.6–7.


Japan’s robust democratic politics and its determined leadership have repeatedlydemonstratedthatoppositionandvetopowerarenotthesame.TheJapan-U.S.SecurityTreatywasratifiedin1960overviolentprotestsandwidespreadoppositionandnowiswidelyembraced.Japan’sSelf-DefenseForces,whichbeganastheNationalPoliceReserveduringtheKoreanWar,became a robust and lethal military force despite Japan’s pacifist constitution andearlypublicopposition.TheSDFhasneverbeenmorewidelyembracedby the Japanese public than it is at present.

ThepostwarhistoryoftheJapanesemilitaryisfilledwithexamplesofgovernmentrestrictionsapplied,onlytobeloosenedatalaterdate.ThiswasthecasewithJapan’sacquisitionoffighterjets(firstdenied,thenallowed),aswellasitsacquisitionofmid-airrefuelingcapabilities,legislatinganabilitytodeployoverseas,useofouterspacefordefensepurposes,andnowthepossibledevelopment of a long-range strike capability.82Moreover,whileapprovalforaweapons-relatedprogramsurelywouldbeevenhardertoobtainfromlocalofficialsthanapprovalfornuclearpowerreactors,itisworthnotingthatsomeprefecturalgovernors,suchasIsseiNishikawafromFukui,supportnuclearpowerastheleadingemploymentvehicleintheirprefectures.Andsomegovernors,suchasShintaroIshiharaofTokyo,haveopenlyarguedforacquiringnuclearweapons.Weaponizationworkcouldbedoneinprefectureswithsupportiveleaders,eveniftheyhostednoreactors.

Finally,evenifJapan’splutoniumstockpileinEuropeisoutofreachandmuchof the separated fuel is controlled by private firmsworriedabout repercussions in international markets, more than enough is held domesticallyundertheaegisoftheJapanAtomicEnergyAgency(JAEA),agovernmentalunit.TherestisheldbyJapanNuclearFuelLimited,whichis nominally a private firm, but one that performs public functions under closegovernmentsupervision.EvenallowingthatonlytwotonsofJapan’splutoniumstocksarebothownedbythestate(throughtheJAEA)andpresentin Japan, and that this might be the only plutonium available for Japanese weapons,thisamountalonewouldbeenoughtobuildalargenucleararsenalofseveralhundredweapons.Inshort,itisnotclearhowmuchofaconstraintcontendinginterests,privateownershipofweaponsmateriel,andtheoverseaslocationofmuchofJapan’splutoniumwouldactuallyplaceonJapanifitweretodecidetomovefrombeingalatenttoanopennuclearweaponsstate.Themotivation, not the obstacles, is the critical factor.

82TheJapanesegovernmenthasstudiedandconsideredacquisitionofalong-rangeconventionalstrikecapabilityinthepast,mostnotablyduringtheNationalDefenseProgramGuidelinereviewof2004.Asimilarstudyisunderwayin2013.AuthorinterviewwithaMinistryofDefenseofficial,February20,2013.Foralistofthe“salamislicing”ofrestrictionsontheJapanesemilitary,seeSamuels, Securing Japan.


Discount FactorsTherearefouradditionalconstraintsthatwouldrequireJapan’sleaders

todiscountthecostsofdramaticpolicychange:(1) thevulnerabilityoftheJapanesepopulationtoafirststrike,(2) theunderminingofJapanesediplomacy,(3) regionalinstability,and(4) damagetobilateralrelationswiththe United States.

Japan’s central vulnerability is its lack of strategic depth. The argument hereisstraightforwardandhasoftenbeenrepeated.ThemajorityoftheJapanese population is clustered in a small number of densely populated urbancenters.BecauseafirststrikeagainstTokyo,Osaka,orNagoyawouldcrippleJapan,nuclearweaponshavelittlemilitaryutility.83Whilesuperficiallycompelling,thisargumentishardlydispositive.ItdidnotpreventGreatBritainorIsrael,withtheirsimilargeo-demographicprofilesandsameprimaryally,fromdevelopingnucleararsenals.TheIsraelicase, infact,impressedsomeJapanesewithhowvulnerabilitycanbediscountedintheface of an existential threat.84NorwouldweexpectastrikeonNewYorkorLosAngelestobeanylesscripplingtotheU.S.nationaleconomy.Moreover,Japan’spopulationdensityandvulnerabilitytoafirststrike—particularlywhenitsarsenalisstilllimited—couldprovideastrongmotivationtodeployanindependentabilitytowipeoutNorthKorea’snucleararsenalpreemptively.

Second, there is the loss of benefits derived from Japan’s diplomatic postureasanon–nuclearweaponsstate.LegalwithdrawalfromtheNPTistechnicallyveryeasy—itrequiresonlya90-daynoticetotheotherpartiestothetreatyandtheUnitedNationsSecurityCouncil—butthecostsassociatedwiththerepudiationofdecadesofJapanesediplomacyandthenullificationofmanyofthebilateralagreementsthatundergirdtheJapanesenuclearpowerprogramwouldrequireasteepdiscountbythecountry’sdecision-makers.Still, many of these leaders are concerned that the nonproliferation regime has been eroding, and Japanese diplomacy is already less strident on this point.Additionally,whetheroneagreeswiththislogicornot,supportersofa Japanese indigenous nuclear program have long argued that Japan neutered itself diplomatically by opting out of the nuclear club and that, from a realist perspective,Japanwouldfortifyitsdiplomacyoverthelongrunbychangingits stance.

Third,anuclearbreakoutwouldcertainlytriggeroracceleratearegionalarmsrace—onethatwouldrequireaconsiderablygreaterinvestmentindefensethanpostwarJapanhasheretoforeaccepted.IfSouthKoreahad

83Thiswasacentralargumentineveryofficialstudyofthenuclearweaponsoption.See,forexample,Hughes,“WhyJapanWillNotGoNuclear(Yet)”;andMochizuki,“JapanTeststheNuclearTaboo.”

84 GroupIchigaya,“KakubusonakiNipponniasuwanai,”2007.


notyetbrokenout,itsurelywouldafteraJapanesedecisiontodoso.SouthKoreanshavelongbeensuspiciousofJapan’snuclearhedging,andtheSouthKoreanmediaandits“unnamed”governmentsourcesregularlyfeedtheperceptionthatJapanisjusta“fewscrewdriverturns”fromafunctioningweapon.85EventheformerambassadortoJapan,Chul-hyunKwon,explainedontherecordthat“Japandidn’tdeclarehavingnuclearweaponsbuttheymadetherawmaterials,andthey…areinfactgettingridoftheobstaclesonebyoneastheopportunityoffers.Inthelongterm,Iguesstheyarepreparingforanuclearweapon.”86AJapanesenuclearbreakoutwouldnotsurpriseSouthKorea,butneitherwoulditbemetwithsympatheticunderstanding.

ChinaandRussiawouldlikewiserespondbyrepositioningandpossiblystrengtheningtheirstrategicforces,andChinainparticularwouldpushtoisolateJapandiplomatically.Additionally,NorthKoreacouldbeconvincedthatitsrecklessbehaviorhasbeenrewardedwithnewalignmentsintheregion.Itisunderstandable,then,thatmanyinJapanseenomilitarybenefittobegainedfrombreakout;instead,theyworrythatanew,higher-costroundintheextantsecuritydilemmawoulddetractfromJapanesenationalsecurity.87ButifJapanactedinresponsetoabreakoutbySouthKoreaortosignificantprovocationbyotherstates,then,asNobumasaAkiyamasuggests,“nuclearproliferationinAsia…mightlowerthethresholdevenforJapantoviolate international agreements and treaties.”88

Fourth,theUnitedStateshasworkedceaselesslysincethe1960stokeepJapanfrombecominganuclearweaponsstate,arguingthatextendeddeterrence is a nonproliferation tool. According to one confident former Japanesediplomat,“theUnitedStateswouldneverallowJapanesenuclearweapons.”89ButwhatifthedrawdowninU.S.budgetsandWashington’sdesiretobalanceChinacollideontheJapanesearchipelago?WhatiftheymeetintheformofareversalofU.S.policytowardJapanesenucleararmament,especiallyagainstabackdropofanevenmoredangerousNorthKoreathatthreatenstodrawtheUnitedStatesintoanuclearwar?GivencurrentU.S.budgetarytrends,exhaustionfrommorethanadecadeofwar,andtheUnitedStates’ refusal to act alone during the Arab Spring, it is not far-fetched to imagineWashingtondeterminingthatitcannolongerprovideregional,

85 See,forexample,Tae-HoKangandParkJung-Won,“IlbonhaekmujanghamyeonHankookdo‘matdaeeung’”[KoreanCounter-action,IfJapanSeeksNuclearArmament],Hankyoreh,October19,2006.

86 Sang-MooHwang,“IlboneuihaekmujangchujinkwahDongbukahjungsae”[Japan’sNuclearArmamentandthePoliticalConditionsonNortheastAsia],KBS News, July 1, 2012.

87 KitaokaShinichi,“Kitanokakuoyokushisurutamenoitsutsunosentakushi”[FiveOptionstoDeterNorthKorea’sNuclearWeapons],Chuo Koron,December2006.

88 Akiyama,“Socio-politicalRoots,”90.89 Authorinterviewwitharetiredambassador,Tokyo,March27,2013.


muchlessglobal,strategicpublicgoodsonitsown.Inotherwords,itishardly inconceivable that economic need and existential threat could trump vulnerability in nuclear strategy and overcome political constraint.

The Durability of the U.S. Security Umbrella amid New ThreatsDespite shifting threat perceptions among Japanesepolicymakers,

Tokyo’s level of confidence in U.S. security guarantees remains high due to the Obama administration’s emphasis on diplomatic and military investments inAsia,Washington’sbipartisanemphasisontheimportanceofalliances,and robust U.S. support for Japan during the tsunami and nuclear disaster in 2011.Inthemediumterm,however,JapanesestrategistsarecloselywatchingtheU.S.responsetoSino-JapaneseconfrontationintheEastChinaSeaovertheSenkaku/DiaoyuIslands.Formany,thisisarepresentativeortestcaseoftheUnitedStates’capacityanddeterminationtodeterChineseaggression.90 Moreover,ananticipatedone-thirddropinU.S.defensespendingfrom2010to2015andcongressionalresistancetofundingbaserealignmentplansintheAsia-PacificraisedoubtsforsomeinJapanaboutU.S.stayingpowerinthe region over the long term.91Thus,whilethereisnoimminentlossofconfidence, certain trends are unsettling to the leadership in Tokyo.

Oneof thesetrends is thedecline inthequalitativeadvantagethattheallieshavetraditionallyheldoverChina’sarmedforces.Asoneanalystopined,“iftheU.S.-ChinamilitarybalanceinEastAsiareachesparity,thenthecredibilityoftheU.S.nuclearumbrellawillbegravelyshaken.”92 On this view,ChineseandNorthKoreannuclear-forcemodernizationprogramswillexacerbate the decoupling problem for Japan. But such modernization could also accelerate U.S. rethinking of a possible Japanese breakout. Although a decisionbyJapantoacquirenuclearweaponsmaynotbeintheUnitedStates’currentinterest,Washington’sabilityandwillingnesstopreventitwouldwaneovertimeifChina’scapabilitiesweretocontinuetoexpandandespeciallyifNorthKorea’sstatusasanuclearpowerweretobecomeanormalpartof

90 AuthorinterviewswithanLDPDietrepresentative,aretiredambassador,aformerseniorintelligenceofficial,andanadvisertotheprimeminister’soffice,Tokyo,March26–27,2013.

91 ClarkA.Murdock,KelleySayler,andRyanA.Crotty,“TheDefenseBudget’sDoubleWhammy:DrawingDownwhileHollowingOutfromWithin,”CenterforStrategicandInternationalStudies(CSIS),October18,2012,http://csis.org/files/publication/121018_Murdoch_DefenseBudget_Commentary.pdf.

92 NakanishiTerumasa,“‘Nipponkakubuso’nogironwohajimerutoki”[TheStartofJapan’s“NuclearDebates”],in“‘Nipponkakubuso’noronten:Kokkasonritsunokikiwoikinukumichi”[Debateson“Japan’sNuclearArmament”:HowtoSurviveThisCriticalMomentinNationalExistence],ed.NakanishiTerumasa(Tokyo:PHP,2006).


the strategic environment in Asia. Under such conditions, Japan’s desire for nuclearweaponswouldappearmorereasonableandhardertocounter.93

The United States is taking steps to reassure Japan and shore up deterrence throughcloseconsultationandeffortstoupdateplansandcapabilities.ButifWashingtondecidestosustainextendeddeterrence,itwillhaveatoughertimedemonstratingconsistencyandendurance.Inyearspast,theUnitedStates’reassurancemethodsfluctuated,beginningwithsignificantforwardpresenceintheregion(bothconventionalandnuclear)thatpavedthewayforJapan’slow-coststrategyofbasicdefense.WhentheColdWarendedandU.S.relianceonJapanseemedmoreequivocal,symbolsoftheUnitedStates’presence and commitment became important, such as the maintenance of force levels in the region above 100,000 personnel.94WhenU.S.forcelevelseventuallydropped,Washingtonemphasizedunderlyingcapabilitiesasthecriticalfactor,andthiswasalsotrueonthenuclearfront—forexample,toutingtheTLAM/Ntocompensateforlowernumbersandthenconventionalstrengthanddual-capableaircraftwhentheTLAM/Nwasretired.95Iftheallies’conventionaladvantageoverChinadeclines,however,andU.S.defenseplanners decide that U.S.-based strategic bombers can address nuclear threats moreefficientlythanintroducingdual-capableaircraftintothetheater,thenWashington’s“reassurancestory”willnodoubtneedtochangeagain.

Alternative Strategic Paths

Tothispoint,ourreviewofJapan’snuclearweaponsoptionshaselidedat least four alternative paths to more independent nuclear deterrence for Japanwithintheallianceframework.ThefirstthreeinvolvesharingnuclearweaponsthatarenotofindigenousdesignandoverwhichJapanwouldhave less than full control. The fourth involves significant enhancement ofJapan’sconventionalstrikecapabilities.Alltheseoptionswouldrequiremajor changes to Japanesedefensepolicyandpossibly constitutionalreinterpretation or revision.

Inthefirstofthethreeacquisitionscenarios,JapancouldopttobuyorleaseU.S.weapons.Japaneseanalystshaveraisedthepossibilityofaleasedealwithasunsetprovisionforuptotwohundrednuclearwarheadswith

93 AuthorcommunicationwithThomasChristensen,February15,2013.94 See“Japan-U.S.JointDeclarationonSecurity:Allianceforthe21stCentury,”MinistryofForeign

AffairsofJapan,April17,1996,http://www.mofa.go.jp/region/n-america/us/security/security.html.95 Forrepeatedemphasisoftheroleof“unrivaled”U.S.conventionalmilitary“preeminence,”as

wellasmentionoftheoptiontoforwarddeploydual-capableaircraftandthepotentialvalueofaconventional“promptglobalstrike”weapon,see“NuclearPostureReviewReport,”U.S.DepartmentofDefense,April 2010, 6, 7, 20, 28, http://www.defense.gov/npr/docs/2010%20nuclear%20posture%20review%20report.pdf.


cruisemissiles.Undertheagreement,theUnitedStateswouldretaincontrolovertheelectronicmapsloadedontothewarheadsandarightoflaunchrefusal.96AlthoughsuchanapproachwouldstillrequireJapantocrossmanyofthesamelegalanddiplomatichurdlesthatitwouldfaceinbuildingitsowndeterrent,whileaddingnewhurdlesfortheUnitedStates,itwouldbethequickestandcheapestwayforJapantoacquireandmaintainnuclearweaponsandcouldbeeasilyreversedifdesired.Forexample,intheeventofKoreanunification and denuclearization, Japan could simply terminate the lease andreturntheweaponsandinfrastructure.Amongthemanycomplicatingfactors, it is hard to imagine the U.S. government providing active support toa JapanesenuclearweaponsprogramifSouthKorea isemphaticallyopposed.Presumably,Seoulwouldhavetakenanuclearstepfirst(withsomesympatheticunderstandingfromWashington)andwouldgrudginglyaccepta Japanese nuclear lease.

The second option could be modeled on the extant arrangement between theUnited States and theUnitedKingdom,whereby BritainleasesU.S.-madeTridentIImissiles,co-developsaspectsofthesubmarineplatform,andmanufacturesitsownnuclearwarheadaccordingtocertainU.S. specifications, including the use of some U.S.-made non-nuclear components.97Thisapproachwouldbelessreversibleandmoreexpensivethanthe“turnkey”leasemethoddescribedabove,butitwouldallowJapantoscaleupitsnuclearprogrammorequicklyandsomewhatmoreaffordablycomparedwithhomegrownoptions.Eitheroftheseapproaches,however,assumesaU.S.attitudetowardtheNPTandtheMissileTechnologyControlRegimethatisfundamentallydifferentfromitscurrentstance,andwouldbe feasible only in the context of a collapse of the global nonproliferation regime.Still,onecanimaginehowU.S.policymakerscouldviewthiskindofapproachaspreferabletoapurelyindigenousJapaneseeffort,notonlybecauseitwouldmaintainalliancetiesbutalsobecauseitwouldprovidefora coordinated means of rollback if future conditions permitted.

A third alliance-based option could follow the NATO model ofnuclear burden-sharing, bywhichU.S. nuclearweapons are deployedon allied territory under U.S. control until a crisis erupts. At that point, followingU.S.authorization,responsibilityforthedeliveryoftheweapons

96MasahiroMatsumura,“PrudenceandRealisminJapan’sNuclearOptions,”BrookingsInstitution,November10,2006,http://www.brookings.edu/opinions/2006/1110japan_matsumura.aspx.

97 SeeJeniferMackbyandPaulCornish,eds.,U.S.-UK Nuclear Cooperation after 50 Years (Washington,D.C.:CSISPress,2008).


devolves to the allied host state.98Beforethen,theallywouldparticipateincommand-and-controlarrangementsanditspilotswouldbetrainedinnuclearwarfightingdoctrine.Althoughsuchburden-sharingarrangementsweremorewidespreadduringtheColdWar,thereremainapproximately150B-61sdeployedatbasescontrolledbythealliedhostnationsTurkey,Italy,Belgium,theNetherlands,andGermanyfordeliverybytheirF-16sorTornados.Thelegalityofthesearrangements,however,haslongbeendisputedunderArticles1and2oftheNPT.99

EachoftheseoptionsgoesbeyondJapanpossessingafewbombsbutfallsshort of a fully independent and survivable Japanese nuclear force. All three would,ofcourse,requirerelaxationofJapan’sthreenon-nuclearprinciplesandthereintroductionofU.S.nuclearweaponstobasesonthearchipelago.Eachwouldallowmorerapiddeploymentthanapurelyindigenousdeterrent,andeachrequiresU.S.cooperation.ManyJapaneseanalystswhowriteonnuclearissues,however,advocategreaterautonomy.NisohachiHyodo,forexample,hasarguedforaforceoftwosubmarinesroamingseparateseaswithonemissileeach,whileKanItoandYasuhiroNakasonerecommend“smallsize”Japanesenuclearweapons.100MitsuoTakaiargues,however,thatareliablysurvivableJapanesenuclearstrategytodealwithChinaorNorthKoreawouldrequireamuchlargerforce—uptosixnuclearsubmarineswiththreehundredhigh-yieldnuclearwarheads—whileTakayukiNishihassuggestedthateventhismightbetoosmallaforcetodealwithafoelikeChina.101Eitherway,thislevelofmilitarizationwouldcontradicttheJapaneseConstitution’sprohibitionof“warpotential,”ascurrentlyinterpretedbythegovernment,whichmakesadistinctionbasedonscaleofdestructivepower.102 Ultimately,Nishi’sconsiderationofnuclearstrategyconvinceshimthatthebestapproachforJapanremainsnuclearabstentioncoupledwithmissiledefenses,aslongasthegrowthofChina’snuclearmissileforcelevelsoff.

98 SeeCatherineMcArdleKelleher,“NATONuclearOperations,”inManaging Nuclear Operations, ed.AshtonB.Carter,JohnD.Steinbruner,andCharlesA.Zraket(Washington,D.C.:BrookingsInstitution,1987);HansM.Kristensen,“U.S.NuclearWeaponsinEurope:AReviewofPost-ColdWarPolicy,ForceLevels,andWarPlanning,”NaturalResourcesDefenseCouncil,February2005,http://www.nrdc.org/nuclear/euro/euro.pdf;andThomasMaettig,“TacticalNuclearWeaponsinGermany:TimeforWithdrawal?”NuclearThreatInitiative,March1,2008,http://www.nti.org/analysis/articles/tactical-nuclear-weapons-germany.

99 AuthorcommunicationwithOwenCote,June10,2013.Onthelegalquestions,seeOtfriedNassauer,“NuclearSharinginNATO:IsItLegal?”BerlinInformation-CenterforTransatlanticSecurity,April2001,http://www.bits.de/public/articles/sda-05-01.htm.

100 YoshiharaandHolms,Second Nuclear Age, 124–25. 101 Takayuki Nishi, “Nuclear Strategy as a Constraint on Japanese Nuclear Armament” (paper

presented at the 52nd annual convention of the International Studies Association,Montreal,March17,2011).

102 JapanMinistryofDefense,Defense of Japan 2013 (Tokyo,2013),143,http://www.mod.go.jp/e/publ/w_paper/pdf/2013/22_Part2_Chapter1_Sec2.pdf.


This raises the fourth alternative deterrence strategy, a much discussed non-nuclearonethatwouldmaintainJapan’snuclearhedgebutentailaconsiderableenhancementofitsconventionaloffensivecapabilities.Asonedefense planner has explained, there is much more Japan can do to augment itsdeterrentshortofnuclearweaponsbreakout.103 Although Japan’s self-imposedbanontheacquisitionoflong-rangestrikecapabilitieshasbeenthinnedbysuccessivereinterpretationsoftheconstitution,theMODbudgethasremainedstatic,andthemilitaryhasbeenslowtoacquirethecarriers,bombers,strikefighters,andballisticorcruisemissilesthatwouldexpandJapan’s capacity to punish adversaries at a distance.104 But some Japanese leaders are seriously considering the need to augment U.S. capabilities. One seniormilitaryofficerinvokedacommonmetaphor:“wehavebeenatourparents’ knee [oya no sune ni kajiru], but U.S. shins have become thin.”105 HejoinsachorusofdefenseplannerswhoadvocatechangingtheextantalliancemodelinwhichtheUnitedStatesisthe“sword”andJapanisthe“shield”tooneinwhichbothcountrieshaveoffensivecapabilitiessufficientto deter regional aggression.106AsNarushigeMichishitahasreported,“themostwidelydebated”militaryoptionforJapangoingforwardistheacquisitionofstrikecapabilitiesforpreemptivecounterforceoperationsagainst hostile bases.107

This“strikecapability”movementreachedaclimaxduringthedraftingoftheNationalDefenseProgramGuidelinesin2004,whentheJDAsoughtfunds to develop long-range, surface-to-surface missile technology.108 But theLDP’scoalitionpartner,theNewKomeitoParty,vetoedthatproposalandtheplanwasdropped.TheAbeadministrationputthisissuebackonthetableforconsiderationin2013afterSouthKorea’sdecisionin2012toextend the range of its ballistic missile forces to eight hundred kilometers

103 AuthorinterviewwithaNationalInstituteforDefenseStudiesofficial,Tokyo,March25,2013.SeealsoMochizuki,“JapanTeststheNuclearTaboo,”314.ThisisconsistentwiththeplansoftheObama administration. See Washington Post, June19,2013.

104 TheSelf-DefenseForceshaveacquiredthebasicsforcounterforceconventionalstrike,includingattackfighters,airbornerefueling,andjointdirect-attackmunitionsthatconvertgravitybombsintoprecision-guidedmunitions.SeeMichishita,“Japan’sResponse,”108.

105 AuthorinterviewwithJapanesemilitaryofficer,Tokyo,March27,2013.106 ThisconvergingsentimentwasheardinmultipleinterviewswithseniorofficialsattheMinistry

ofDefenseandwithformerMOFAandintelligenceofficialsinTokyo,March25–27,2013.107 Michishita,“Japan’sResponse,”107.Headdsthatsome(unnamed)securityspecialiststhinkthat

acquisitionofthesecapabilitiescouldactuallyunderminethealliancebygivingWashingtontheoptionofnotdefendingJapan.Fora2006studyonthisissuebyaninfluentialJapaneseanalyst,seeSugioTakahashi,“DealingwiththeBallisticMissileThreat:WhetherJapanShouldHaveaStrikeCapabilityunder ItsExclusivelyDefense-OrientedPolicy,”NIDS Security Reports, no. 7(2006):79–94.

108 “Draft of Next Midterm Defense Buildup Plan Seeks Missile Research,” Kyodo News, December3,2004.


provideddiplomaticcover.SuchashiftcouldenhanceJapan’sdeterrenceposture,whetherornotitwereintegratedwithU.S.militarydoctrineinwaysthatwouldmakedeterrencemoreeffectiveandcredible;however,italsorisks complicating the regional security dilemma and engendering domestic politicalblowback.WashingtonhaslongpushedforamoremilitarilycapableJapanbutisreluctanttoweighinpubliclyonthissensitiveissue,lesttheUnitedStatesbeviewedaseitherencouragingorrestrainingJapan.Onthislatterpoint,inparticular,theU.S.sideisawarethateffortstodissuadeTokyofrom adding strike capacity could be unsuccessful and might accelerate the lossofJapaneseconfidenceinitsally,therebypromptinganevenquickerdevelopment of independent capabilities.

Conclusion

HenryKissingerhassuggestedthatthelogicofwarshiftedwiththeintroductionofnuclearweaponsinwaysthatareconnecteddirectlytoissuesexaminedinthischapter.Hestatedthatbeforethenuclearage“theconsequencesofabandoninganallyweredeemedtobemoreriskythanfulfillingone’sobligations.IntheNuclearAge,thisrulenolongernecessarilyheldtrue;abandoninganallyriskedeventualdisaster,butresortingtowarat the side of an ally guaranteed immediate catastrophe.”109ItisofnolittlesignificancethatthispassageiswellknownamongJapan’sstrategicelites,manyofwhompointtothedecliningcredibilityofextendeddeterrenceandthefactthatnonproliferationnormshavealsowithered.

CampbellandSunokawa,whoinsistthataJapanesenuclearbreakout“wouldbepotentiallycatastrophic,”havewarnedU.S.leadersandpubliccommentators against raising questions about extended deterrence orencouragingJapantoconsideralternativestoitsnuclearhedgedstatusquo:“Americanleadersandinfluentialcommentatorsbothwithinandoutsidethegovernment should never signal to the Japanese, even inadvertently, that they actuallyfavorJapan’sacquisitionofnuclearweapons.”110Butaswehaveseen,thoughtful Japanese security specialists have not needed encouragement to cast an unsentimental and realistic eye on the future of extended deterrence. TheyhaveneedednopromptingtoraisequestionsaboutJapan’sstrategicdefense and to interrogate U.S. overextension.

Equally thoughtful international security specialists in theUnitedStateshavebegunaskingsimilarquestions.MichaelJ.Mazarr,aprofessor

109 HenryKissinger,Diplomacy (NewYork:SimonandSchuster,1994),608.Notethatassecretaryof state Kissingermanaged alliance relations successfully and assured allies thatWashingtonwouldcometotheiraid.

110 CampbellandSunohara,“Japan:ThinkingtheUnthinkable,”219,246.


ofnationalsecuritystrategyattheU.S.NationalWarCollege,isconcernedaboutU.S.“strategicinsolvency”—thepursuitof“yesterday’sstrategyundertoday’sconstraints”andtheUnitedStates’growinginabilitytomanagethegapbetweenitsstrategiccommitmentsanditsnationalobjectives.111 Barry Posenarguesthat

extended deterrence is a very risky business, and the United States ought to have beengladtoshedsuchcommitmentsaftertheColdWarended.Instead,theUnitedStatesretainsextendeddeterrencecommitmentsinEuropeandAsia….Extendeddeterrenceremainsaplausiblepathtooneormorenuclearweaponsbeing used either against U.S. forces or the U.S. homeland.112

PosenlaysoutfouroptionsforJapanbeyonditsalliancewiththeUnitedStates.Twoarelow-probabilitycoursesofaction:thatJapancouldfindanewnuclearprotectororthatitcouldbandwagonwithChinaorotherrivals.Echoingsomeofthestrategistsexploredinthischapter,PosenobservesthatathirdoptionisforJapantopersistwithitsnuclearhedge,whichhesaysistantamountto“ignoringtheproblem”andwhichoneDietrepresentativecalled“closingoureyesandwhistlingpastthegraveyard.”113 The fourth option, nuclear breakout, is the one that has been explored in this chapter in its several possible forms.

LikeIsrael,whichhasclimbedmuchhigherupthenuclearweaponsladder,JapanhasassumedwhatVipinNaranglabelsa“catalyticposture,”onethat “relies on an ambiguous nuclear capability aimed at ‘catalyzing’ third-party—oftenU.S.—militaryordiplomaticassistancetodefendthestatebythreateningtounsheatheitsnuclearweapons.”114 To assume this posture, havingassemblednuclearweaponsisnotevenstrictlynecessary—onesimplyrequiresthe“abilitytoassembleahandfulofnuclearweapons.”Giventheavailabilityofasuperpowerpatronandotherconstraintsonmoreovertchange,thisposturemaycontinuetoserveJapanesesecurityinterestswellandisTokyo’smostlikelychoiceshoulditopttofollowIsrael.ManipulatingthethreatofbreakoutremainsamechanismtokeepWashingtoninthegameinEastAsia.

Still, as this chapter has shown,much remains uncertain in thechangingEastAsiansecurityenvironment.NorthKorea,inparticular,isanunpredictableactorandagrowingthreattoalterTokyo’scalculus.Atpresent,fewvoicesintheJapaneseorU.S.strategiccommunitiesopenly

111 MichaelJ.Mazarr,“TheRisksofIgnoringStrategicInsolvency,”Washington Quarterly35,no.4(2012):8.

112 Posen,U.S. Grand Strategy,97.113 Ibid.,102;andauthorinterviewwithanLDPDietmember,Tokyo,March27,2013.114 Vipin Narang, “Posturing for Peace? Pakistan’s Nuclear Postures and South Asian Stability,”

International Security34,no.3(2009/10):41.


advocateaJapanesenuclearbreakout.ButgivenquestionsabouthowtheemergenceofamultipolarnuclearAsiawillcomplicatenationalandalliancestrategies, the possibility cannot be dismissed. Both communities should beawarethatextantconstraintsonsuchadramaticshiftcanbestretched,that threat perceptions can change, and that a range of once unthinkable alternatives is available.