An Expanded NATO's Nuclear Strategy

Yoko Iwama

1. NATO's Nuclear Strategy in the Cold War Era

NATO's nuclear strategy during the Cold War was in essence the massive retaliation strategy. The US administration of President Eisenhower, inaugurated in 1953, reviewed the previous US defense strategy and announced in early 1954 the "massive retaliation strategy" that relied heavily on nuclear deterrence. This was incorporated into NATO's strategy in December of that year. The North Atlantic Council (NAC) adopted a strategic document MC 48, which confirmed the policy of intensive use of nuclear weapons in the early stages of a defensive war. The Eisenhower administration adopted its massive retaliation strategy for political and military reasons. The Korean War, which had imposed significant financial and human burdens on the United States, ended at last; and there appeared a political trend seeking to reduce defense spending and to return society to normalcy. 1 During his election campaign, Eisenhower employed a lot of rhetoric to the effect that he, unlike Truman, would use US forces more boldly to soon end the Korean War and focus on economic and social recovery. For the United Kingdom also, which at that time was in dire financial straits and desperate to maintain the British empire, it was in its interest to reduce conventional forces in favor of nuclear deterrent; the British situations facilitated the Eisenhower administration's change of strategy. 2

After his election, Eisenhower's political message that the threat of using nuclear weapons was instrumental to ending the Korean War had much to do with formulating his massive retaliation strategy. In the spring of 1953, Eisenhower ordered that nukes be made available as ordinary weapons; in the summer of the same year, he intimidated China by implying the possibility of using nuclear weapons, stating that the resumption of combat operations would invite consequences "so grave that, in all probability, it would not be possible to confine hostilities within the frontiers of Korea." 3 Effectively, China and the DPRK had already lost their willingness to continue the war, and Stalin's sudden death added momentum toward a cease-fire. This constituted a successful experience for President Eisenhower. 4

Even before taking office as Secretary of State in the Eisenhower administration, Dulles believed that the United States must strengthen deterrence against the DPRK and China by underscoring the threat of nuclear use instead of deploying US ground troops on the Korean Peninsula. From his experience in the US-occupied Japan, Dulles felt that the presence of US military bases and large number of foreign troops would likely strengthen anti-US sentiment. He believed that containment supported by nuclear deterrence and offshore air and naval forces would be preferable. At that time in Europe, the presence of Soviet ground forces was overwhelming. West Germany had completely been demilitarized; the British and French forces were meager in number. Eisenhower did not want to continue stationing large numbers of US troops there. Therefore, the United States needed to formulate a strategy that would not necessitate the deployment of large numbers of soldiers. Stalin's death was followed by détente in Europe. The urgent sense of crisis that an East-West war might start had faded away compared to 1950.

As soon as it adopted the massive retaliation strategy, the Eisenhower administration began deploying many tactical nuclear weapons to US forces in Europe. The mid-1950s was a time when all US military branches competed to develop nuclear weapons, and a wide variety of tactical nuclear weapons were developed and deployed. Although many of these weapons are no longer in use, the period from the late 1950s, when missile ranges were extending day by day, until the arrival of the ICBMs in the 1960s, was the golden age of tactical nuclear weapons' development. Since Eisenhower initially believed that nuclear weapons should be used "as ordinary weapons," they were increasingly deployed on the front lines, aided by NATO's strategy of their early use to stop Warsaw Pact forces advancing westward. If tactical nuclear weapons were to be used in the earliest stages of warfare, they had to be stockpiled on the front lines in advance so that field commanders could employ them in a timely manner. 5

As a result, during the Eisenhower administration, the number of NATO nuclear weapons increased at an extraordinary pace. This increase was due to various factors, including the presence of SAC commander Curtis LeMay and the structure of the US bureaucracy; Eisenhower may not have necessarily wanted the magnitude of the increase, but it occurred under his political responsibility. 6 No nation has ever before or since built nuclear weapons at the pace that the United States did in the late 1950s. The configuration of the East-West confrontation, completed by 1960, was to define the nature of nuclear deterrence until the end of the Cold War. As Figure 1 clearly shows, the number of Soviet nuclear warheads trails along behind the US nuclear warheads. Stalin's policies in the early Cold War era always followed the moves of the West; the establishment of the Warsaw Pact Organization came only after West Germany acceded to NATO, six years later than the North Atlantic Treaty had been signed. Even in his later years, Stalin did not give up on the idea of a neutralized unified Germany; the Stalin Note of March 10, 1952, illustrates this fact. 7

Fig. 1: Estimated Global Nuclear Warhead Inventories

Source: Federation of American Scientists, Status of World Nuclear Forces,

The Eisenhower administration was proactive about providing nuclear weapons to the allies. However, it could not do so under the provisions of the domestic Atomic Energy Act. In the late 1950s, the United States worked out a new system, in which the US provided nuclear-capable weapons to its allies in advance, stockpiling nuclear warheads in Europe under NATO's nuclear stockpile system. These warheads will be provided to the allies with those nuclear-capable weapons when actual war started. 8 Since the Eisenhower administration desired to reduce US forces in Europe assuming an early-stage use of tactical nuclear weapons, it was logical to expect the European allies to shoulder greater responsibilities, including the possible use of tactical nuclear weapons.

In addition, the Eisenhower administration proposed a multi-national operation of strategic nuclear weapons, whereby multinational crew would jointly operate a Polaris missile armed submarine. This developed into what later came to be known as the Multilateral Force (MLF). 9 This proposal was in the end abandoned by the Johnson administration, but the system which was called the "nuclear stockpile" at that time survived and is now caleed "nuclear sharing." This arrantement was started around 1958-9 under bilateral frameworks between the United States and each ally, and a large number of nuclear carriers were introduced under this system during the Cold War.

2. Adoption of the Flexible Response Strategy and the Establishment of Nuclear Sharing and Consultation System

If one compared Figures 2 and 3, they will notice that the US nuclear deployments on shore in Asia peaked in 1967 and begins to decrease after that. Also, in Europe, US nuclear deployments have leveled off or slightly decreased after their peak in 1967. Yet, the number of nuclear weapons supplied to non-US forces continued to increase until about 1971, raising the overall number of weapons. US nuclear warheads at sea (see Figure 4) reached their peak in 1963. The US nuclear strategy changed its direction with the advent of the Kennedy administration. It shifted from the previous strategic direction of increasing the number and types of deployed nuclear weapons as much as possible, thereby aiming for deterrence with the advantage of overwhelming forces, to one of limiting the number and types of nuclear weapons and of controlling the entire nuclear arsenal to prevent a nuclear war that the United States did not wish. Since arms procurement takes years, the shift of strategic direction does not mean that the number of nuclear weapons will immediately begin to decrease, and a policy change will also take time. When the Kennedy administration came to power, it was astonished by the lax control of nuclear weapons during the Eisenhower era; the new administration immediately strengthened control of warheads by several means including the introduction of the PAL (permissive action link) system.

Fig. 2: US Nuclear Deployments in NATO Europe

Fig. 3: US Nuclear Warheads on Shore in the Pacific Region

(Figs. 2, 3 Source: Robert S. Norris, William M. Arkin & William Burr, "Where they were," Bulletin of Atomic Scientists, Vol. 5, No.6, November/December 1999, pp. 26-35.)

Fig. 4 US Nuclear Warheads at Sea, 1945-2015

Source: Federation of American Scientists, "Declassified: US Nuclear Weapons At Sea," By Hans Kristensen, February 3, 2016.

Under the Eisenhower administration, the US Army conducted a research project on what a war using tactical nuclear weapons would look like. The effort was named the Pentomic Division, which sought to make divisions smaller and more mobile to minimize the damage sustained from the use of tactical nuclear weapons on battlefield. However, those concerned with this research project concluded that no matter what measures they took, it would be inevitable that if both enemy and friendly forces used many tactical nuclear weapons on Central European battlefields, soldiers and civilians would suffer serious losses. Eventually, the project was abandoned in 1963. 10 By the early 1960s, the massive retaliation strategy had clearly failed. The employment of many tactical nuclear weapons against Warsaw Pact forces advancing westward was an unrealistic choice. NATO conducted several nuclear-war exercises, including the famous "Carte Blanche." All of them suggested that, in actual warfare, casualties would number in the millions. Naturally, the casualties were to include NATO soldiers.

In the early 1950s, the general public did not yet fully understand the possible damage caused by nuclear fallout. However, following the Fifth Lucky Dragon incident, information about the likely damage caused by atomic bombs became widely known in the late 1950s; and from 1957-8, anti-nuclear movements and nuclear abolition movements began to spread worldwide. Such a movement first appeared in Japan because of the Fifth Lucky Dragon incident. In several years that followed, the Soviet Union and the United Kingdom successfully tested hydrogen bombs, whose enormous destructive power soon became well known. People became aware that the number of nuclear weapons in the world had already reached tens of thousands; the image of nuclear war as the destruction of the world became firmly rooted and still survives. At the same time, this also meant the establishment of the so-called "nuclear taboo," or the norm of not using nuclear weapons. 11

Due to several multiple causes, there was already a shared understanding within the Kennedy administration at the time of its inauguration that nuclear weapons were difficult to employ, that the US military already had more than enough nuclear weapons, and that the actual risk lay more in the outbreak of an unwanted accidental nuclear war as a result of possessing too many nuclear weapons that could not be well controlled. This recognition was further enhanced by the Berlin-Cuba crisis, and as a result, the increase in the number of nuclear warheads slowed and peaked in the 1960s. Because of concerns about the control of nuclear weapons deployed in the allied countries, the United States decided to bring them back home as much as possible. Although there may have been some resistance from the military, most of the tactical nuclear weapons deployed in the Asia-Pacific region were either retired or moved to Guam or the US mainland in the late 1960s, because the host nations in Asia-Pacific did not have a strong say or desire to deploy nuclear weapons (as was the case of Japan). The reversion of "an Okinawa with no nuclear weapons and the same as mainland Japan (Kakunuki Hondonami)" seems to have been possible because it coincided with this period.

A strategy that materialized the Kennedy administration's strategic thinking was the so-called "flexible response strategy." Discussion of the strategy at the earlier stage went in tandem with the theory of limited nuclear war; theoretically, the limited use of tactical nuclear weapons is not necessarily inconsistent with the flexible response strategy. In Asia, however, the nuclear threshold was in reality raised, and the number of tactical nuclear weapons decreased sharply in the 1960s. The Kennedy and Johnson administrations intended to limit the use of nuclear weapons as much as possible; to rely on strategic nuclear weapons as the ultimate deterrent, and to strengthen American control of whatever remaining nuclear weapons. The administration's intention is evident from the US nuclear posture in the Asia-Pacific region. Using nuclear weapons was discussed during the Vietnam War, but it did not seem to be effective enough to change the war situation, and hence the US government concluded that the possible benefit of the use of nuclear weapons would not offset the political downside. 12

In Europe, however, nuclear weapons continued to increase during this period. In particular, nuclear weapons intended for use by non-US forces continued to increase due probably to political issues inherent to NATO: the question of the balance between nuclear and conventional weapons in NATO had always been intertwined with that of the credibility of US extended nuclear deterrence. After the advent of the Kennedy administration, Secretary of Defense McNamara attempted to introduce in NATO the strategy of flexible response, thereby reducing reliance on nuclear weapons. Soon he encountered the political problem that the reduction of nuclear weapons deployed in Europe might endanger the credibility of US extended deterrence. Any US action considered to weaken US military commitment would cause "abandonment anxiety" on the part of the allies. In addition, European countries were not ready to expand their conventional forces, which would be necessary if they were serious about the flexible response strategy. During this period of political calm and stable economic growth, there was no room in those countries for a significant increase of military budget. 13

In the 1957-68 period, the so-called global nuclear order was established. It was a regime seeking to control the possibility of the use of nuclear weapons by limiting the number of nuclear weapon states, while concurrently providing a sense of security to non-nuclear states through extended deterrence and participation in arms control and disarmament regimes. In the NATO-led nuclear order, the dominant US nuclear arsenal provided extended deterrence to the entire alliance while the United Kingdom and France possessed a minimum nuclear arsenal and would use it for the benefit of NATO as the situation might demand. The political prerequisite for this was that non-nuclear states should maintain trust in the US extended deterrence. To this end, an operational system for tactical nuclear weapons, which gradually came to be known as "nuclear sharing," and nuclear consultation system centering on the Nuclear Planning Group (NPG), created in the late 1960s, constituted the two pillars of the order. 14 These were coupled with the finalization of the non-nuclear status of countries other than the United States, the United Kingdom, and France, which meant the accession to the NPT.

The first nuclear consultation among the NATO allies probably date back to discussion on the possibility of US nuclear use during the Korean War. When the Eisenhower administration decided, at the end of 1953, to use nuclear weapons against China in case of the failure of cease-fire talks, the United Kingdom and France—especially the British administration—strongly demanded that any nuclear use must be accompanied by prior consultations. 15 The possession of nuclear delivery means and the storage of nuclear warheads (by the US military) for the purpose of nuclear sharing system are based on bilateral agreements between the United States and each of the host countries. On the other hand, the NPG discusses nuclear operations and strategy as the issues of the NATO alliance. Although initially, there were different treatments among the member states, the NPG today is an equitable organization with the participation of all members except France.

NATO claims to have adopted its "flexible response strategy" in December 1967, but the premise of forward deployment and early defensive use of tactical nuclear weapons remained unchanged. Although the term "massive retaliation" disappeared, strategically, NATO continued to depend heavily on deterrence through the use of nuclear weapons and possible escalation to all-out nuclear war. As a result, thousands of tactical nuclear weapons remained in Central Europe until the late 1980s, ready to be used at short notice any time if necessary.

In Europe, unlike the markedly anti-Communist WWII generation, the postwar generation felt a strong repulsion about this situation; NATO's strategy of relying on nuclear deterrence gradually lost the support of domestic public opinion. This issue reached its zenith in 1983 due to the deployment of intermediate-range nuclear weapons to US forces in Europe based on the NATO Dual Track Decision. The most widespread anti-nuclear and anti-NATO demonstrations occurred in West Germany, but there was also significant opposition in other European countries. The "modernization" of nuclear weapons, even if it entailed a reduction in the total number of nuclear deployment, only gave the impression that "new nukes were coming," undermining the support of domestic public opinion. The escalation of the issue into a genuine alliance crisis was only averted, thanks to the emergence of Gorbachev in 1985. After 1985 the East-West tensions were reduced and the move to disarmament set in, leading to the end of the Cold War. Nonetheless, by 1985, NATO's nuclear problem had, due to their inherent contradictions, given rise to extreme political tensions within the alliance. 16

3. Transition to the Post-Cold War Era

When the Berlin Wall fell in November 1989 and negotiations for the unification of the two Germanies began, the issue of a unified Germany and nuclear weapons should naturally have been a significant focal question. If the Soviet Union had only conducted a better oriented diplomacy, a denuclearized-, unified Germany might have appeared. Public opinion, at least in West Germany, had turned very anti-nuclear by the late 1980s. Anti-nuclear weapons and anti-nuclear power had become a policy issue shared by the two leftist parties, the Social Democrats and the Greens. These liberal parties were at the same time substantially anti-NATO and rather wanted to create an all-European security system out of the CSCE (Council for Security and Cooperation in Europe). The unification of the two Germanies was regarded as something that should occur within the framework of a unified Europe. Undoubtedly, the European integration was important, but particularly in West Germany, people longed for a comprehensive all-European security institution rather than dividing security organizations like NATO and the Warsaw Pact Organization.

The Soviet Foreign Ministry experts were well aware of the above and believed they should demand, if possible, the neutralization, or at least, the denuclearization of a unified Germany. However, Gorbachev did not necessarily respect the views of these experts in the 1990 negotiations; what he acquired through his often arbitrary and inconsistent diplomacy was only a promise that the West would not deploy any nuclear weapon in the former East German territory. The so-called Two-Plus-Four-Treaty on German unification renounced in Article 3 the production, posession, and control of ABC weapons, continuing compliance with the NPT. A ceiling of 370,000 troops was imposed on unified Germany. Until the withdrawal of Soviet forces was completed, only German forces not integrated into NATO were allowed to deploy in the former East German territory. After the withdrawal of Soviet forces, German troops integrated into NATO could be stationed in the same region; but nuclear delivery means were not allowed to deploy there (conventional-nuclear dual-use weapons were permitted limited to their conventional use). Deployment of foreign troops, nuclear weapons, or nuclear delivery means in the former East German territory was not allowed (Article 5).

Russia and the West would later dispute over the meaning of this Article 5. Russia asserted that the West had promised that NATO would not expand further eastward. The Two-Plus-Four-Treaty refers only to the treatment of the former East German territory. The treaty is the postwar settlement of Germany, not that of the Eastern European countries, much less the whole of Europe. The West accepted the denuclearization of the former East German territory, but otherwise, they obtained their utmost demands accepted by Russia. Among the Western leaders, US Secretary of State Baker temporarily considered pledging the non-expansion of NATO eastwards; West German Foreign Minister Genscher also temporarily considered non-accession of a unified Germany to NATO and its neutralization. However, the US and German leaders never agreed on these conditions. Nor did the Soviet side consistently demand these conditions. In the end, the unification of Germany was achieved on the best possible terms that Chancellor Kohl and President Bush had in mind. 17

President Bush, who had refused the denuclearization of Germany, rapidly removed US ground-based nuclear weapons from Europe following the end of the Cold War. On September 27, 1991, in an announcement called the Presidential Nuclear Initiative (PNI), he announced the removal of all US ground-based tactical nuclear weapons overseas and of all tactical nuclear weapons from US surface ships and attack submarines "under normal circumstances." 18 As a result, US nuclear forces in Europe rapidly decreased (see Figure 5). The only nuclear weapons not planned for reduction were the B61 bombs designated for nuclear sharing. These were to be carried by the allies' fighter aircraft known as DCA (dual-capable aircraft). Around one hundred B61s are estimated to be currently stored in several different places in Europe under US force's control.

When Bush announced the PNI, the Soviet Union was on the verge of collapse. The United States feared that Soviet tactical nuclear weapons estimated at 22,000 might become dispersed. The smallest ones of those weapons were said to be small enough to be carried in a duffel bag; if it were to fall into the hands of terrorists, the result would be unpredictable. The Bush administration launched preparations to announce a unilateral disarmament plan in the hope that the Soviet Union might take a similar move. Vice President Cheney was skeptical, but the supportive views of National Security Advisor Scowcroft eventually prevailed. NATO Secretary General Wörner, contacted for consultation, agreed to the plan on condition that the air-delivered systems would remain intact in Europe. President Gorbachev was contacted about the plan by the United States on the morning of September 27. 19

By the end of the year, the Soviet Union and the Warsaw Pact Organization were gone; Russia, in political turmoil, was no longer a military threat. Thus, for the first time in its history, NATO was freed from the assumption of defending itself against Russian tanks advancing westward by using tactical nuclear weapons. Since the 1990s, NATO has continued to declare that it will remain a nuclear alliance; the B61 bombs of the NATO nuclear sharing arrangements are probably its symbol. For about a generation, for the first time in its history, NATO was freed from the obsession about nuclear strategy.

Fig. 5 US Nukes in Europe (Source: Robert S. Norris and Hans M. Kristensen, "U.S. Nuclear Weapons in Europe, 1954-2000," Bulletin of the Atomic Scientists, November/December 2004)

4. NATO Enlargement and Nuclear Deterrence

In 1990, the enlargement of NATO toward the former Warsaw Pact countries was discussed, but no decision had been taken. Czechoslovakia and Poland had already begun to secretly approach NATO for membership. Yet, a further eastern expansion of NATO did not occur until the United States ultimately made a decision—which the Clinton administration made in 1994-5. Accession to NATO necessitated the assurance of, among other things, a certain level of democratization of the emerging countries' armed forces. Poland, Hungary, and the Czech Republic joined NATO in 1999. In 2004, NATO underwent a second round of expansion, and seven countries, including the three Baltic states, joined the alliance. Since 2009, it has further expanded to include the Balkan states. Today the member states number 30.

As mentioned above, the 1990 "Two-Plus-Four-Treaty" pledges to not introduce nuclear weapons into the former East German territory; however it does not mention countries located further east. As a result, NATO expanded eastward, and Russia repeatedly claims they have been "betrayed." NATO insists that there was no promise of non-eastward expansion; meanwhile, it is refraining from permanent stationing of foreign troops and deployment of nuclear weapons in former Eastern European countries. Since the Russian invasion of Crimea in 2014, Eastern European countries have been calling for upgrading territorial defense; NATO has, in effect, gradually increased the presence of troops in Eastern Europe and the Baltic states, albeit not in the form of permanent stationing. On the other hand, there has been, to date, no outstanding movement on the nuclear arms front: the number of B61s remains reduced while no change has been reported in NATO's nuclear strategy.

The only new NATO-related development since the Russian invasion of Ukraine in 2022 is Germany's announcement to purchase F-35As. This move has ensured the continuation of NATO's current arrangement of nuclear sharing for the foreseeable future. The German Tornado jet as a DCA was aging, and there was concern that if the present model failed to undergo renewal, it would lead to a gradual German withdrawal from nuclear sharing. 20 When a new German government came to power at the end of 2021, there were strong concerns that it would decide in its coalition agreement to decide to withdraw from the nuclear sharing arrangement. Many emphasized the necessity of the existing system to maintain NATO's nuclear deterrence, and ultimately the new government refrained from making such a decision. Particular emphasis was placed on the possibility that if Germany withdrew from the nuclear sharing arrangement, Poland and the Baltic states might become concerned and want to have US nuclear weapons deployed on their territories. Poland and Romania have often called for more US military presence, but the United States has, so far, deployed only missile defense-related assets to those countries. With the start of the war in Ukraine, the United States announced strengthened US troop presence in Europe but has not mentioned building up their nuclear arsenals.


For a long time after the Cold War, there had been no military threat to NATO on the European continent. As a result, NATO turned into an organization focused on "out of area operations," first in the former Yugoslavia region and then in Afghanistan, where it engaged in peacekeeping and peacebuilding activities. The resurgence of the Russian threat is forcing NATO to reconsider the significance of territorial defense once again. To date, however, discussion among NATO member states has centered on how to provide military support to Ukraine, not on how to conduct NATO's territorial defense and to restore deterrence. Despite Putin's nuclear threats, there has been no official argument for building up the nuclear arsenal of US forces in Europe.

During the Cold War, NATO adopted a defense strategy that relied excessively on nuclear deterrence and the early-stage use of tactical nuclear weapons. But the political cost associated with it was quite high. In the 1980s, NATO was torn apart by the public opinion opposing nuclear weapons and faced repeated alliance crises. At present, opposition against nuclear weapons remains strong in Western European countries; a certain taboo still lingers against discussing the reintroduction of nuclear weapons or a defense strategy that would increase dependence on nuclear deterrence. This situation will probably not change unless Russia resorts to tactical nuclear weapons. Will Europe undertake a military buildup that would enable it to sufficiently defend itself by conventional forces alone? The key will be Germany's decisions. Chancellor Scholz has repeatedly stressed that Germany has changed, using "Zeitenwende" (turning point) as the key phrase for his foreign policy in 2022. But after one year, not much has changed in the Bundeswehr; most of the special defense fund of 100 billion euros Scholz pledged has yet to materialize; Germany's defense spending has so far increased only minimally. It will take time before German diplomacy undergoes a genuine shift.

(Professor, National Graduate Institute for Policy Studies)

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