NATIONAL INTELLIGENCE ESTIMATE
SINO-SOVIET AND FREE WORLD REACTIONS TO US USE OF NUCLEAR WEAPONS IN LIMITED WARS IN THE FAR EAST
RELEASE IN FULL
DIRECTOR OP CENTRAL INTELLIGENCE Tne following inielligence organisations participated in Ihe preparation ol this estimate: The Centra! intelligence Agency and lhe intelllgeice organizations of the Departments ollhe Army, the flaxy, lhe Air Force, and The Joint Staff
Concurred in by lhe
INTELLIGENCE ADVISORY COMMITTEE
j"aUiicarr'nghe Director ofnd Research, I'cparlmentieti: the Atstslani Chief of Staff. Intelligence, Department Ol rhe Army;irector ol A'nwi inidUgmce the Assistant Chief cf staff, fntelh-gence, USAP; the Deputy Director (or Intelligence. The Joint Staff; and the Atomic Energyti Representative to lhe IAC. Thr. Assistant Director. Federal Bureau ofabstained, the subject being outside of his jurisdiction.
CENTRAL INTELLIGENCE AGENCY
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S1NO-SOVIET AND FREE WORLD REACTIONS TO US USE OF NUCLEAR WEAPONS IN LIMITED WARS IN THE FAR EAST
This estimate was requested by Uie NSCesulttudy prepared by the Departments of Stale and Defense and the Joint Chiefs of Staff, with appropriate participation of the Central Intelligence Agency, on US and Allied Capabilities for Limited Military Operations9mong the limitations under which this study was prepared were that It did not examine US and Allied eapabililies against overtly employed Soviet armed forces; nor against an enemy employingweapons, since the latter case was construed as ovcri employment of Soviet forces. On the other hand, it was assumed that the US used nuclear weaponsfrom the outset in four hypothetical cases involving Communist aggression in the Far Fast.
This estimate examines whether or not the enemy would employ nuclearif thc US employed them, and assesses lhc impact on world attitudes if either the US or both sides employed them. It confines itself to assessing the above reactions in the four hypothetical cases given in thc State-Defense study where the USnuclear weapons at thc outset in response to Communist aggression throughI) North Korean invasion of Southhinese Communist attack on Quemoy andhinese Communist attack on Taiwan,orth Vietnam attack on South Vietnam and Laos. It is based on the hypotheticalwhich are developed inf the State-Defense study and which are summarized ul the outset of1 of this estimate.
We believe Uiat If thc US used nuclear weapons in meeting Bloc local aggression in Uie Far East, there wouldrave risk that the Comnninisls would retaliate in kind Indeed any Far Eastslate, taking into account thcof such US action, would be unlikely toocal aggression withoutreceived assurances of Soviet suppoi t
2 Wc estimate thai, though the USSR will be determined lo avoid courses of aciion gravely risking general war throughout the period concerned, itcalculates that its growing military capabilities likewise increasingly deter the US from taking such risksthc Soviets would probably estimate lhat local Communist use of nuclear
weapons in direct and localized response to their use by thc US would notlead to expansion of hostilities into general war, and they would undercircumstances be prepared to use such weapons.
If the Communists retaliated withweapons, they would attempt to do so inanner as to limit the risks of general war. The USSR itself would probably prefer to avoid openand would probably provide the necessary weapons to Communist China or North Korea, though retaining Soviet control. Moreover, the Communists would probably confine their use ofweapons within limits comparable to those observed by Uie US.
The likelihood of Communistwith nuclear weapons would be greatest if the US mounted nucleardeep into Communistituation to which Moscow andwould almost certainly feelto respond by attacks on US bases and nuclear capable forces in the Far East. If, in the case of Communist aggression against South Korea orthc US nuclear response wereto Korea or the Straits area, thc Communists would probably respond in kind in Uie same area. In the case of local aggression against Quemoy and Matsu or South Vietnam, Uieresponse would be less certain. If US nuclear attacks were confined to thc immediate Quemoy and Matsu areas or Vietnam and Laos, Uie Communists might attempt to win without usingweapons or seek to break oft the action. However, even if the US nuclear response were limited to thc immediate area of Korea. Taiwan, Quemoy and
Matsu, or Vietnam and Laos, we cannot exclude thc possibility that thewould respond in kind, possiblynuclear attacks against US bases in the area selected to minimize therisk of general war.
Many Free World governments and countries would be impressed andby the prompt US resistance to Communist aggression, but Uie US use of nuclear weapons would arousefear of general war and would tend to obscure Communist responsibility for initiating hostilities. The US would be widely condemned by popular opinion, especially in Asia, for the use of nuclear weapons. We believe that the adverse reactions would overshadow the favorable effects in most countries.
The adverse reacUon would beif the US response quickly halted the fighUng without causing largecasualties, and respect for US power would be enhanced. Even so, the stigma resulting from the US iniUation of thc use of nuclear weapons would not beOn the other hand, if thcresponded with nuclear weapons and hostilities were prolonged andfears of general war would rise even higher, and great pressure would be exerted on thc US loettlement.'
Deputy Director lor Intelligence, the Joint Stan, agrees wllh ihe principal conclusion* that:
a US nuclear response to Communlit aggres-Ion would be likely ta result In Bloc response wiih nuclear attacks in the first two casesand leas likely In the second two cases
onsiderable adverse political andreaction, particularly In Alia, wouldrenull Irom US nuclear attacks.
The DDI, Joint Stan, disagrees, however, wllh certain Irv.njudgments andyardsticks npplled in Ihese conclusion* and tn lhe supporting discussion He believe" (Footnote continued on page 31
THE GENERAL SINO-SOVIET MILITARY REACTION
A. Factor! Bearing on tho InitialDecision to Altack
n our view the crucial determinant In any Sino-Soviet decision to initiate localor subsequently to respond In kind to US use of nuclear weapons in countering such aggression, would be the Slno-Sovlet estimate of the resultant risks of general wax. Weto estimate that respect for US nuclear power will remain such that neither thenor the Chinese Communists arc likely to pursue courses of action which in their judgment seriously risk general war. Largely for this reason, we do not believe that any ol the four hypothetical cases of Communist aggression considered in this esUmate Is likely to occur through
(Footnote continued from page 21
paper (alls to recognize adequatelyof selective US use of nuclearspecifically, It tends to equategeographical limitations on targetalso applies to weapons yield,target choice, and accuracy ofthese factors, references to "heavyappear incompatible with the
paper reaches certain qualitativeas to the relative weights ol adversereaction and favorable popular reactionnuclear attacks: these relaUveare largely conjectural Suchappear to fall lo give due weight towhkh would Influence popularin addlUon to the fact that theemployed nuclear weapons Some offactor* would be the InlUalby US military forces, Ihc publico( US governmental Icadcisobjectives and intentions, and thc extentpopular opinion clearly recognisedaction as resulting IromThere would certainly ba bolhand boos, to say that tn mostboos would drown out Uioould overshadow .Isu precision of estimating notfor Iho hypothetical situations
We must assume, however, for thc purposes of this estimate, that such aggression has taken place. Several consequences (low from this assumption. Most important, thewould have launched this aggression only after careful calculation of the likelihood of US Intervention and of thc resultant risks of general war. Bolh US statements and the general poslure of the US forces In the Par East would almost certainly lead them totlml US intervention with nuclear weapons would be Lhe only immediatelyUS response.
The moat likely calculations, therefore,which the Communists would decide to launch local aggression in the Far East would be that the chances that the US would be deterred fromocal nuclear response were sufficient to Jusiify taking the risk and that even If the US did respond, their own capabilities were sufficient both lo cope with this reaction and to deter the US fromthe conflict to general war. Thismight arise in the case of aiikrcase in Communist capabilitiesis those of the US, especially in the Far Eastas lor example by the possibleof nuclear weapons and advancedvehicles In Communist China.in this situation,c leaders might estimaLc that Lhe US would be unwilling to accept thc risks and the adverse Free World reactions Involved in responding wllh nuclear weapons to Uloc attacks, and being unable to respond effectively In any other manner, would choose not to do so at al).
believe it most likely Hint anyaggression in the Far East wouldonly in full consultation withsince the Chinese. North Koreans,Vietnamese would almost certainlyupon certain guarantees of Sovietevent of US retaliation beyond theirlo counter However, we cannotthe possibility of unilateral actionpart of Uie Chinese Communists, basedcumulation that despite Sovietthe USSK would be compelled to come
lo their support if the US replied with nuclear weapons. We regard such adventurism asalthough possibly less so In the case of Quemoy and Matsu.
any event, regardless of theirthe likelihood of US nuclearCommunists almost certainly wouldplans and preparations to meet thisIf the decision to launch ahad been taken well in advance,have already provided Peipingnuclear weapons and perhapsof delivery, both toSand to counter it if It came.that in any event the Chinesethe USSR for such weapons, andUSSR may introduce these weaponsChinalthough theycertainly remain under Sovietthe Soviets might promiseto provide them quickly withif required. Moscow wouldattempt to deter the US at thethe aggression by threats oyinterventlonthe US uses nuclear weapons.
B. Factors Bearing on the Subsequent Communis! Reaction
Once Communist local aggression in the Far East had been launched, and the US had responded locally with nuclear weapons,and Peiping wouldriticalBroadly speaking, their reaction might range from abrupt termination of the conflict or seeking negotiations, through continuing the fight with conventional forces, to replying in kind with nuclear weapons.
As already staled, we believe the crucial determinant would be their estimate ol the resultant risks of general war. Moscow and Peiping would be acutely conscious that the risks of general war had materially increased. The very fact Of US use Of nuclear weapons would reflect US determination to accept some risks. We believe, however, that if they had initially launched the aggressiona US nuclear response and if they were confident of their capability to deal with it locally, they would promptly react withweapons themselves.
If, on the other hand, Moscow andhad miscalculated our response, they might be more disposed touickon thc basis of the status quo ante rather than further increasing the risk of general waruclear response of their own. Even in this case of initial miscalculation, however, the Soviets might regard their over-all nuclear deterrent power as making US resort towar sufficiently unlikely that they could afford to take the risk ofuclear response. Moreover, they would haveadditional reasonsuclear response, among them; (a) considerations of prestige,oviet feeling that"havingdire consequences if the "US intervened with nuclear weapons, they must save face by following through; (b) tho vulnerability of the US bases in the Far East; (c) on theside, the importance of supporting their chief ally; and (d) the damage to the Soviel deterrent posture if the USSR failed to
The manner in which the US employed nuclear weapons couldritical bearing on whether or not the Communistsuclear response. II such use were highly selective, and above all if confined to thearea of hostilities, the Communists might not respond wiih nuclear weapons But especially if the US launched nuclear strikes deep into Communist China, Peiping would almost certainly appeal desperately for Soviet assistance, and we believe that thewould feel compelled to come to theof their chief ally. They would probably calculate that they could not afford the loss to the Bloc and the blow to their own prestige and positionrippling of Communistpower.
The Communist reaction would also be conditioned by their appreciation of theUS posture at the time They would look to other US military movements, the degree of alert in the US. and US statements forof whether the US was preparing torolonged local war if necessary, tothe conflict, or toeturn to the status quo. In this connection US statements of the limited nature ol our objectives, ifwith our military actions, might have
considerable Impact. Such statements might tend to reassure the Communists that atermination of the conflict on anbasts was feasible. On the other hand, these statements might reassure them that their use of nuclear weapons locally would not lead the US to broaden the conflict.
it appeared to the CommunistsUS was not prepared to expand theor torolonged war. theybe more inclined to continueusing nuclear weaponson thc other hand thc US. whileinitial nuclear response, neverthelessdetermined to press on to victory,to expand the conflict in theif necessary, the Communisttend to be more cautious. Theylaunch some nuclear attacks tostrike capabilities in an attempta stalemate, but they wouldmove to secure an early end to
C. The Modes ol Sino-Soviet Nuclear Rosponso
case tlie Communists decided tonuclear weapons if the US had usedin the Far East. Peiping andMoscow would nevertheless do soa manner as to limit the risks thatwould expand into general war.reason we believe that the Sovietsloath to intervene directly throughSoviet forces to attack USforces. They would probably preferto provide the necessary weaponsto thc Chinese Communists orthe North Koreans. We believe theycalculate Uiat the limited US basein the Far East would be highlyeven to attack by Chinesealone. But thc Soviets wouldaid and support,liey would almostSoviet forces to participate in theof Communist China Moreover,of widespread US attacks onwe cannot exclude the possibilitySoviet intervention In thc Far Kast.
and Moscow's desire.to limitol general war also would probablyto confine their nuclear attackscomparable to Uiose observed byIf US use of these weapons wasthe immediate combat area, we believeCommunists would similarly limitHowever, the possibility cannotthat even if US use of theseconfined to the Immediate combatCommunists might also launchagainst US bases in the Westernselected so as lo minimize the dangerwar. If the US attacked targetsCommunist China, the enemy wouldreact by attacking selected US basesWestern Pacific.
FREE WORLO REACTIONS
Free World reactionsS response with nuclear weapons to CommunistIn the Far East would vary widely.that the aggression were clearlymost of our allies, and probably some neutral opinion, would be inclined, at least initially to view with approval our prompt and forthright aid to the victim of attack.this feeling would be overshadowed by fear that nuclear war in Uie Far Easi would spread into general war. Such apprehension would rise greaUy if the US nuclearwere ofaturefor example strikes deep Jnto Communist Chinathat it appeared to be in excess of the force required, and particularly if the Communists employed nuclear weapons inEven If the war were localized there would be fear that one side or the other might subsequenUy broaden It These developments would lead to strong pressures on the part of other governments torompt end to hostilities.
Along with Free World fear of expanding hostilities wouldidespread adversereaction to US use of nuclear weapons Should these weapons inflict large casualties, particularly among civilians. It wouldthis feeling. If. however. US use ofweapons leduick victory without large civilian casualties this attitude of repug-
nance would tend to diminish and to be ollsct by confidence In US deterrent power.
adverse reaction to US use ofweapons would be particularlymost of Asia. Here suchlend to be looked upon as callousto the lives of Asians. Indeedot large-scale casualties onmight have enduringly adversefor the anti-Communist positionTlie reaction in Japan would beadverse, in view of deep Japaneseantagonism to the use of nuclearand Japan would probably not allowof bases on Its territory. Themight be mitigatedimitedif the Communists In turn employedweapons, but the US would stillodium of having used them first.
HE CASE OF NORTH KOREAN INVASION OF SOUTH KOREA
It is assumed for theof this estimate thatime whenIn South Korea is confusedPresident Rhee's Incapacitation, andare seeking power, the NorthSouth Korean border violations,subversive activities in South Korea,invade. Chinese CommunistNorth Korea is covert, including troopsas North Koreans. II is alsomost US lorces have beento the attack However, the USinitially largely with air power,subsequent commitment ol groundnecessary. The US uses nuclearenemy military targets in Koreathe destruction of which Isto successful prosecution ofThc US seeks UN backing, or,the support of the other fifteenthe UN Command, but does not awaitbefore intervening.
A. The Sino-Sovicl Military Reaction
lie initial Communist attack on the ROK would probably only have been undertaken In anticipation that victory could be gainedUS counteraction, or lhal lhe US would
be deterred from effective counteraction by the chaotic situation within the ROK. allied hesitancies, and fear of Sino-Soviet counter-moves. Nevertheless, the Sino-Soviet leaders, recognizing Uiat thc US might use nuclear weapons In Korea, would probably beto counter this development by similar local use of nuclear weapons.
if the initial US reaction were quick,and limited to Korea, thc Bloc might attempt toease-fire, cut its losses, and redress its loss of face, in thc belief Uiat the fruits of victory were not worth Uie risks of expanded wai. In this case it wouldto exploit politically the-US use ofweapons, but we regard It as more likely that Uie Chinese Communists and North Koreans would reply with nuclear weapons obtained from the USSR.
If US use of nuclear weapons wereto North Korean targets, thewould probably use nuclear weapons only against targets in South Korea.we cannot exclude the possibility that if the attacks were launched from outside.Korea, the Communists might also launch nuclear attacks against US bases selected so as to minimize Uie additional risk of general wareven though thc US strikes had been confined to Korean territory.talemate developed on Uieew armistice would be sought.
likelihood of Communist nuclearwould be greatest in the event thatattacks were directed againstChina itself Thc Chineseprobably aitack with nuclearUS bases and naval forces in theIf ballistic missiles capable ofthese targets had been deployed inlo the aggression, they would also
ree World Reactions
Bloc aggression appearsUie general attitude of lhe Freeeven including India andwould initially bethe ROK nnd Uie United Stales. A
large measure ol diplomatic support would be forthcoming and some of our allies would be inclined to ofTcr some token militarythough the US could not count on any significant Free World military support
Free World sympathy would begenerally by fear that the conflict would expand since thc US had used nuclearparticularly if the US attacked targots outside of Korea. Our principal NATO allies would probably seek to restrain the United States from continuing nuclear attacks. The neutralist countries would almost certainly have backed away from any initial approval. Conversely, if the Communists did not launch nuclear attacks, or if the conflict werelocalized, concern over thc spread of hostilities would diminish, and initial Free World approval of the US action wouldbe strengthened. Even so. if heavy civilian casualties were inflicted, it would probablyeeling of revulsion,In Asia, against the US.
From the outset, the Japanese reaction would constitute one of the greatest problems for the US. While the government and much of the public would be sympathetic to the US-HOK cause, fear of Japan's involvement would create great pressures to deny the United States the use of Japanese bases. US use of nuclear weapons, whatever the targets, would Inflame Japanese reactions, public andalmost certainly to the point ofthat the US not use its bases in Japan for nuclear attacks. Japan might even insist on complete US withdrawal, particularly If thc US expanded air attacks beyond Korea.
IV. THE CASE OF CHINESE COMMUNIS!
ATTACK ON QUEMOY AND MAfSU
Two weeks ofaltack on the offshore islands,of jet fighters and bombers inChina area, and concentrationassault forcesomingGRC supply and reinforcement ofbecomes difficult, due to heavyIn this charged atmosphere.spokesmen recall0 Sino-Soviet
Treaty of Mutual Assistance, and the US in turn stresses its Mutual Defense Treaty with the GRC. The US informs out allies that it will assist in repelling an Invasion, usingweapons, if necessary against mainlandeneral alert is declaredthe Pacific Command. Japan announces It will never permit bases on its territory to be used for atomic warfare. When thebegins, the US immediately provides assistance to tbe GRC including selectiveattacks on military targets. radius from the islands (includingin the Shanghai, Nankin gi and Cantonnd on enemy strike force baseslocated in China, as well as on theforce itself.
A. The Sino-Soviet Military Reaction
Confronted with such an extensiveresponse, Peiping and its Soviet ally would probably feel compelled lo react with nuclear attacks at least on Taiwan and on the Sovcnth Fleet. Whether they would extend their attacks to other US Far East bases would depend largely upon whether these bases were used in our nuclear offensive and upon their assessment of our intentions. It US nuclear. weapons were used extensively againstChinese targets, the Communists would probably feel compelled to respond against other US bases and forces in the Far East
On the other hand, the firmness and promptness of our response would probably convince Peiping of our determination tocontrol of Quemoy and Matsu. If at the same time our attacks were initially limited to forces and facilities in thc immediate area and directly supporting the aggression, this factor might also convince Pclplng that our objectives were limited to defense of the islands Under these conditions, thc Chinese Communists, if they had failed to seize the islands, would probably abandon the attempt despite the loss ot face they would suffer from this defeat. This outcome would be most likely in the remote event that Peiping had launched the aggression without full Soviet concurrence and suppoit. In this situation
the USSR, despite Chinese Communistwould probably seek to close out the actions as quickly as feasible, and attempt to compensate lor Communist military defeat by political exploitation of the US use of nuclear weapons.
B. Free World Reactions
The predominant Immediate Free World reaction to the US use of nuclear weapons against Communist China would be highly adverse, with many allies as well as theconsidering that the US was risking general war over what most of tho worldas unimportant parcels of real estate. Most of our allies, including those in NATO, would probably shun any responsibility for. or connection with, the US aciion, in an attempt to avoid Involvement in hostilities developing from Quemoy and Matsu. In Asia,ew countries, notably Nationalist China and South Korea, would be encouraged by the vigor of the US response to Chineseaggression, whereas strong antagonism would be aroused generally throughout the continent by US use of nuclear weapons.
The adverse reaction would tend to be modified lo tlie degree that thc US action brought the hostilities to an early successful end without heavy civilian casualties. Under these conditions, even some Asian countries would probably come to have greaterin thc ability of the United Slates to defend them against Communist aggression. But the reacUon in most countries wouldadverse.
onversely, if the conflict were prolonged or were to spread, and especially if large-scale casualties were inflicted on Chinese- civilians, the adverse consequences for Uie US might be Irreparable, particularly in Asia We might be forced to withdraw Irom our bases in Japan, and Japanese pressure for ourfrom Okinawa would Increase. Our influence in most other Asian counUies would be seriously undermined In Western Europe feaia of general nuclear war and popular pressures on governments to end the fighting would increase
V. THE CASE OF CHINESE COMMUNIST INVASION OF TAIWAN
ssumptions.esult of effectiveCommunist Interdiction of the offshore islands, the GRC successfully evacuatesand Matsu, unopposed and wiUi lhe assistance of the US Seventh Fleet. Thereuildup of invasion forces and air-power in East China. The GRC calls on thc UN to condemn such war preparations, and asks for military assistance; the US reiterates readiness to aid Uie GRC If It ls attacked. Japan announces It will never consent to Its bases being used for atomic warfare, while Uie Philippines and South Korea-announce their support of Uie GRC. There0 day warning period before Uie actual attempted Invasion, during which US forces could deploy in the area. Upon the actual invasionUie US renders assistance by air and naval forces, employing nuclear weapons against the enemy Invasion forces, enemy bases for Uie attack (including airnd any successful enemyon Taiwan. If this does not fullySAC is to be employed against otherCommunist forces and the warmaking -capabilities of Communist China All present US bases in the area are used, except those in Japan.
A. The Sino-Soviet Military Reactions
ince Chinese Communist invasion of Taiwan would require the commitmentignificant portion of the Chinese Communist armed forces, and would in Pciping's eyes carry great risk of US nuclear intervention, we regard it as almost certain lhal Peiping would not undertake such an operationprior assurances of Soviet supportwc believe that the Sino-Sovietwould have regarded the likelihood of US nuclear intervention lo be sufficiently great lhat Uiey would have deployed Soviel nuclear weapons (under Chinese Communist cover) in East China. In Lhc assumed case, the Bloc would piobably calculate cither Lhal Uie US would be deterred by fear of Bloc nuclearfrom responding with sufficient force
to thwart the Invasion, or that Bloc nuclear capabilities were sufficient to cope wlUi US nuclear intervention.
If the initial US response with nuclear weapons were limited to the attacking forces and the immediate area ot Taiwan, andIf it quickly defeated the InitialCommunist attempt at invasion, the Communists might seek to close out thc war quickly, preferring military defeat towar. They might calculate that their loss of military prestige would In part beby propaganda dividends from US use of nuclear weapons against Asians and that the ultimate effects in weakening the US posilion in Asia might be considerable.
However, the extent to which Chinese Communist prestige had been committed by an operation ul this size and the difficulty ofettlement which the Chinesecould accept without loss of face might lead the Bloc to retaliate with nuclear weapons even if this meant serious risk of expansion of hostilities in the Par East.if they decided to continue thein thc face of US nuclear attacks in the Taiwan Straits area, they would retaliate with similar nuclear attacks upon bases in Taiwan and upon the Seventh Fleet.
If the US extended the area of its nuclear attacks deep into mainland China, wethat tlie chances of Communist nuclear counterblows would be substantially greater The USSH would be faced with the difficult decision either of permitting its major ally toumiliating defeat, or ot taking thc risks involved in the necessary stepsefeat. We estimate that the Communists would launch reciprocal nuclear strikes against selected US bases and naval forces. If ballistic missiles capable ofthose targets had been deployed in China prior to lhc aggression, they would also be used
B. Free World Reactions
though most Free Worldrecognise that Communistclearly occurred. Ihis factor would bfl out-
weighed by concern throughout the Free World lest World War in result from thcUS use of nuclear weapons. Host of our allies, including those ln NATO, would probably think that protection of Taiwan was not of sufficient Importance to warrantwhich they would consider to promote serious risk of general war, or even of major war in the Far East. Some of them would express some support of the US, but they would exert strong pressureeasefire. Popular pressures on Allied governments for ending the fighting would increase, as would sentiment for restricting US ability to launch nuclear strikes from bases elsewhere in the world. Thc US would almost"certainly bethe use of lis bases In Japan for the campaign.
adverse reaction would lend toto the degree that the USthc hostilities to an earlywithout heavy civilian casualties.conditions, even some Asianprobably come to have greaterIn the ability ol the United Stalesthem against Communistthe reaction in most countries wouldadverse
VI. THE CASE OF NORTH VIETNAMESE INVASION OF SOUTH VIETNAM AND LAOS
The Vietnameseinfiltrate the equivalent of twoand as many irregulars into allstates, and concentrate aol regular forces in Northclashes occur and there is cassassinations In Vietnam Presidenta state of national emergencyinvokes the SEATO treaty, and callsfrom all members- There is no clearof the invasion. US militaryinclude the selective use cfas appropriate, against thetargets In North Vietnam, and inareas ot Communist China Themoving, advises Communist ChinaUSSH of its intention lo assistunless lhc invadeis withdraw.
A. The Sino-Soviet Militoryn initialing thc attack on Souththe Bloc would almost certainly have counted on achieving its objectives before an effective US Intervention could develop, and possibly on deterring any US Intervention at all. Once the US nuclear response occurred, the Bloc would be confrontedifficult choice among: (a)egotiated(b) continuing the war without Bloc use of nuclear weapons, calculating that the US would not in this case employ nuclear weapons against Communist China itself; or (c) reacting by use of nuclear weapons against US forces, with the resultant risks involved.
f US use of nuclear weapons wereto targets in Indochina, there Is an even chance that thc Communists wouldto continue the campaign without using nuclear weapons themselves. In this case, the Bloc would continue to provide military assistance and equipment to theuildup of Communist air power. If the Communists were able to continue effective military operations in Soulh Vietnam and Laos despite US use of nuclear weapons the Impact in Asia would beIf US-Vietnamese forces were threatening to crossh Parallel they would probably seek lo close out the conflict on the basis ol restoration of the status qua. Should North Vietnam nevertheless beChinese Communist forces wouldenlet in force lo hold at least the Hanoi Haiphong and northerly areas, In this case,
thc Communists would also probably threaten to usend Indeed might usenuclear weapons in Indochina itself to stave off defeat.
li al any stage the USattacks on adjacent areas lnCommunists would probably respondattacks on targets In Indochina,on selected US bases in other
B. Freo World Reactions
Initial support among Free Worldund peoples for US determination to resist Communist aggression would be offset in large measure If the US used nuclearOpposition to US use of nuclearwould be particularly strong if thc US attacked targets In Communist China, even if Communist Chinese use of "volunteers" in Vietnam were large-scale and widely known. As In the previous cases, opposition to US use of nuclear weapons would be sharpest In Asia.
If the US response Involved only limited and selective use of nuclear weapons Inalone, thc reaction of most US Allies would be less adverse. Such action would have the support of South Korea andChina, and would have the support of some SEATO governments if they thought this action necessary to repel thc aggression. Howcvri. the reaction of most Free World countries, and particularly ol thc Asianwould still be generally adverse, even If lhc conflict remained localized and thewere turned back.Original document.