Policy Papers

North Korea and the nuclear threat

Jenna Phillips |

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Executive Summary

  • The Democratic People's Republic of Korea (DPRK; North Korea) is not yet thought to have developed a ballistic missile capable of carrying a nuclear warhead. However, its second nuclear test has added to fears that Pyongyang is moving closer to becoming a fully-fledged nuclear-armed state.
  • If the DPRK were to use nuclear armaments, the conflict would probably spread and the risk of escalation into global war would be heightened. This is because nuclear weapons and atomic diplomacy are not appropriate for use in limited warfare.
  • Pyongyang is almost certainly aware of the hollow nature of the Western nuclear threat. Just as in 1950-1952, the atom bomb's destructive potential operates as a self-deterrent. Then as now, nuclear capability does not translate into diplomatic leverage.
  • Thus the answer is not for the West to develop newer, more destructive nuclear weapons in the hope that they will deter. Instead, the UN member-states, including China and Russia, should unite in applying stronger diplomatic sanctions.


In April 2009 North Korea fired a long-distance three-stage rocket. Although Pyongyang insisted that this was merely a satellite, it proceeded to expel United Nations weapons inspectors from its main reactor at Yongbyon. The following month, it successfully exploded a plutonium-based nuclear device similar in size to that dropped on Hiroshima in 1945. When South Korea decided to participate in the US-led Proliferation Security Initiative, North Korea abrogated the armistice agreement drawn-up in 1953 at the end of the Korean War. In June 2009, when the UN imposed new sanctions against North Korea, Pyongyang acknowledged its uranium enrichment programme and threatened the US with military action. It also declared its intention to weaponise all of its plutonium reserves (enough for at least six atomic bombs). Then, on 4 July, it launched seven scud-type ballistic missiles, in an apparent act of defiance against the UN.

The UN now faces a dilemma. The North Korean President, Kim Jong-Il, has already broken several promises to dismantle his nuclear project. Under the 1994 Framework Agreement, Bill Clinton offered Pyongyang two light-water civilian reactors and an end to sanctions imposed over forty years earlier. In return, Kim agreed to disable the Yongbyon reactor and to stop building two larger nuclear power plants. Eleven years later, he again agreed to denuclearise. But in 2006, his regime carried out an unsuccessful missile test and exploded a nuclear device underground. This led to the imposition of sanctions by the UN. In 2007, North Korea again promised to immobilize the Yongbyon reactor in exchange for fuel oil and other concessions.

Thus although North Korea is not yet thought to have developed a ballistic missile capable of carrying a nuclear warhead, it is moving closer to becoming a fully-fledged nuclear-armed state. If Kim goes unpunished, other states such as Iran may follow his example or cooperate with him in their bid for nuclear arms.

In the meantime, President Obama's nuclear security policy remains embryonic. Kim's threats will increase hard-line neo-conservative pressure for an increase in US nuclear capabilities against China, Russia and Iran, as well as North Korea. Underlying these calls is the assumption that Washington's nuclear superiority would act as a deterrent. This reasoning stems from rational deterrence theory and focuses on the strategic level (the level at which a nation, usually as part of an alliance, determines national or multinational security aims and develops its resources to accomplish those aims). How credible is that theory, and can it be applied at a local or regional level?

This paper will first address the theory to ascertain whether, in abstract terms, atomic power or diplomacy can be used in a limited war (a conflict restricted militarily or geographically so that the force employed is commensurable to the end objective). It will then examine the evidence, using as a case study Truman's policy during the Korean War. Finally, it will consider how those conclusions might be applied to North Korea today.

Rational deterrence theory

Firstly, in a theoretical sense, can nuclear weapons be used in limited warfare? Can nuclear warfare be limited?

As US economist Thomas Schelling has demonstrated, limits reliant upon degrees of judgement are difficult to impose or maintain - instead limits should enjoy 'some rationale that makes them qualitatively differentiable from the continuum of possible alternatives' (p.30). Those advocating the possibility of limited nuclear warfare have therefore favoured limitations in terms of targets, rather than quantities of weapons. Yet foreign policy adviser Morton Halperin notes the problems involved in the concept of target limitation. Take, for example, the 1950-1953 Korean conflict: even if both sides had explicitly defined foreign territories as unacceptable targets, the use of tactical nuclear weapons within the theatre of war would have increased the temptation, and importance, of including enemy air bases (in Japan and Manchuria) as legitimate targets.

Similarly, theories for limited nuclear warfare based upon deterrence are implausible. While some historians have argued that the strategic deterrence inherent in atomic weapons would prevent the escalation of a limited nuclear conflict into a total (or global) one, this assumes that both sides will act rationally. In contrast, in 2001 the political scientist Robert Jervis showed that misperception can easily lead states to act irrationally, thereby decreasing their national security. For example, in an arms race, an attempt by one actor to augment its own defenses will lead another actor to react in kind. Alternatively, efforts by one state to deter an adversary could frighten that adversary into taking precipitate action, thus leading to a conflict that neither state desires. This phenomenon is known as the 'security dilemma'.

Misperception increases the risk of miscalculation and pre-emptive attack. Indeed, it can be argued that the extreme destructive potential of atomic weapons (and the corresponding insecurity it provokes) reinforces this tendency. Since the full-scale use of nuclear weapons by two or more states could result in mutually assured destruction (the decimation of both sides) any decisive strike would have to be pre-emptive. It is therefore unlikely that limits towards this escalation could be imposed and maintained in any nuclear conflict.

Nevertheless, atomic weapons can be 'used' in two ways: both physically, as a weapon, and psychologically, as a deterrent. Can nuclear deterrence be used in limited warfare? Rational deterrence theory supposes that the destructive potential of atomic weapons will permit a superior nuclear power to deter attackers and achieve political goals. However, there are at least six flaws in this reasoning:

  • As T.V. Paul, James McGill Professor of International Relations, notes, the international abhorrence of, and aversion to, nuclear weapons can convince inferior states that, in retaliating, the possessor will refrain from using its maximum capability and seek to keep the war limited.
  • The destructive potential of nuclear bombs may deter the possessor from using them.
  • Because all-out nuclear war risks mutual destruction, the threat of maximum retaliation may not deter nuclear adversaries.
  • Rational deterrence theory assumes that states base their strategic calculations upon logical, cost-benefit analyses - and, as mentioned above, that is not always the case.
  • It remains unclear as to how the possessor might use the theory to fulfil its political aspirations. It is very difficult to convert a supposed omnipotent military threat into raw diplomatic power.
  • The theory focuses on strategic deterrence between the superpowers. Such analyses cannot be universally applied. Alexander George and Richard Smoke have demonstrated how, in a local conflict, deterrence becomes more context-specific: this increases the difficulties inherent in creating and applying a credible threat.

From a theoretical viewpoint, therefore, one must deduce that nuclear warfare and atomic diplomacy are not appropriate for use in limited warfare.

The Korean War

The validity of this deduction was apparent during the first two years of the Korean War.

The Korean War broke out in June 1950 when Communist-led North Korea invaded South Korea. In response, the American President, Harry S. Truman, intervened on behalf of the south. Meanwhile, the UN established a unified command under US General Douglas MacArthur for the purpose of repelling the Communist invasion. But when MacArthur advanced past the 38th parallel and up to the Yalu River, China intervened, propelling the UN troops back to Pusan. By 1951 the conflict had degenerated into stalemate. Although the two sides opened negotiations in July 1951, they did not agree on an armistice until July 1953. That armistice re-established a borderline similar to the 38th parallel, and Korea remains divided to this day.

The Korean War occurred just five years after World War II, the war of 'unconditional surrender', within a domestic context where anything but 'total victory' was an alien concept. It was America's first modern, 'limited' war, and the first war of the nuclear age. In accordance with rational deterrence theory, Washington assumed that its nuclear superiority would act as a deterrent. In fact, however, the Communists (particularly the Chinese) were aware of the powerlessness of the atomic threat: President Harry S. Truman was unwilling to alienate international opinion by using another atomic bomb, and China lacked the targets required for the weapon to have any decisive effect.

American strategists had focused on the strategic level, but such analyses proved irrelevant in a limited conflict. The Truman administration had neither a readily usable nuclear force in the Far East nor any procedural mechanisms for applying such force at a local level. Meanwhile, defence and counteroffensive capabilities were inadequate in a limited context, leaving ground troops vulnerable to attack. Although a minority of lower-level hardliners called for tactical bombing (the bombing of troops and military equipment within the fighting zone), for top officials this was never a real option.

Similarly, rational deterrence theory proved problematic in Korea. The war's unique complexities increased the difficulty of creating and applying a credible deterrent. This factor, coupled with the belief in a world-wide Communist 'monolith' - the idea that all Communists, regardless of their nationality or political background, were controlled by the Kremlin - undermined attempts at atomic deterrence. It was assumed that one could not attack only China - such action risked invoking the Sino-Soviet alliance. The 'real' enemy was Russia: Pyongyang and Beijing were merely toeing Stalin's line.

Here, four examples will suffice:

1. In July 1950, Truman authorised a modified version of the 1948 Berlin Blockade feint. A deployment of nuclear-configured B-29 planes, accompanied by B-29s carrying non-fissionable atomic bombs, was transferred to England. Following requests by Generals Douglas MacArthur and Hoyt Vandenberg (Chief of Staff of the Air Force) for the pre-positioning of Strategic Air Command B-29s for use in the event of Chinese intervention, the Joint Chiefs of Staff authorised the transfer of ten nuclear-configured bombers to Guam.

For top-level officials, these deployments represented a low-risk venture (the fissionable cores remained under Truman's control) with high potential gains. Their main purpose was to deter Beijing from aggression in Taiwan and Korea. The Chinese invasion of Korea in November 1950 appears to confirm their failure. As Mark Ryan notes, the aircraft returned to America before China intervened, and it is not clear whether Moscow or Beijing perceived the implicit threat. This, therefore, was attempted rather than actual atomic diplomacy - after all, a feint has to be detected in order to deter.



2. On 30 November 1950, Truman remarked at a press conference that there had 'always been active consideration' of using the atomic bomb - the US government would 'take whatever steps are necessary to meet the military situation' in Korea. Ultimately, the decision was a military one - the field commander would be in charge of the use of weapons, as was customary policy.

Some historians have suggested that these comments, far from being a blunder, represented a 'trial balloon' designed to gauge international opinion. But such a high-risk strategy seems unlikely - Truman's statements damaged the administration's standing, especially abroad. Either way, the press conference extinguished any remaining doubts concerning international opposition to atomic bombing in Korea.

By early December 1950 the first and second Chinese invasions had caused a change in Washington's thinking vis-à-vis the bomb. A misperception of Beijing's motives and the focus on strategic deterrence had led officials to miscalculate what constituted a credible deterrent. However, now that the Chinese People's Volunteer Army (CPV) had intervened, the issue of nuclear deterrence seemed irrelevant. Likewise, allied opposition precluded atomic retaliation. Instead, as one government document, JSSC 2173/2, illustrated, the bomb only appeared as a last-ditch defence measure - a means of covering UN forces in the event of an evacuation from the peninsula.





3. In early 1951 fears of Soviet intervention resumed, prompting Truman to authorise the transfer of nine atomic weapons from the Atomic Energy Commission to the US Air Force, to act as a strategic reserve force in a general war. The Senate hearings into the dismissal of General MacArthur and the new Chinese ground-offensive further heightened tensions in Washington. According to Dingman, this led to the 'subtle use' of atomic weapons in an effort to 'deter and restrain' the enemy (p.75).

A Strategic Air Command control team was deployed to Tokyo; air reconnaissance missions over the Chinese mainland were authorised; and the prohibition on atomic weapons was modified. From now on, any major attack on the UN Command from overseas bases was to be met with nuclear retaliation. Washington also dispatched Charles Marshall of the Policy Planning Staff (a State Department think-tank) to Hong Kong, where he warned Chinese envoys that US patience was limited: if pushed too far, America could severely retard the development of Communist China.

Yet these threats were far from explicit and there is little evidence to suggest that the Chinese were deterred. By May, the administration was keen to distance itself from MacArthur's hard-line policies: the Senate hearings publicly reinforced Truman's limited war strategy. Moreover, the administration still lacked the procedural mechanisms for implementing nuclear strikes. Although the pace of atomic development was slowly reacting to - and being forced by - events, there remained no comprehensive procedure for applying atomic power at a local level.





4. In January 1952, Britain and America approved a 'greater sanctions' policy, whereby any ensuing armistice would be backed by a US threat to retaliate against its violation; such retaliation 'would not necessarily be limited' in geographic scale or in the 'methods of warfare' used. In September, the State Department approved various suggestions to covertly spread rumours that Washington appeared increasingly susceptible to pressure from pro-nuclear hardliners. The same pressure, the rumour was to continue, 'undoubtedly will be exerted to extend the bombings to China, using atomic weapons'. The only way to avert this outcome was to 'get an armistice without delay'. The US ambassador to India and Nepal, Chester Bowles, reputedly informed the Indian government that if an agreement were not reached, America would go all-out to win.

Nevertheless, according to his account, Bowles did not explicitly threaten nuclear retaliation. Similarly, it is not clear that the State Department's suggestion (of spreading intimidating rumours) was carried out. As Mark Ryan notes, the Communists had over eight hundred high-performance jets based in Manchuria - enough to counteract the U.S. atomic threat. Moreover, in spite of America's superiority in nuclear weapons technology, UN forces remained vulnerable to atomic attack by Russian TU-4 bombers. Hence both of General MacArthur's successors - General Matthew Ridgway and General Mark Clark - claimed that US defence and counteroffensive capabilities were inadequate. In many respects, therefore, the 'greater sanctions' statement was worthless.

When Clark requested an end to the military restrictions prohibiting the use of atomic weapons, the Joint Chiefs of Staff deferred any decision for the incoming Eisenhower administration. Then, as throughout the period since the North Korean invasion, the Truman government remained unwilling to authorise nuclear warfare. The Korean conflict had demonstrated that the atomic threat was hollow: the bomb's destructive potential could not be converted into political power.


From this analysis we can draw two conclusions about North Korea today. Firstly, if Pyongyang did use nuclear armaments, the conflict would probably spread: during a limited war, both sides limit the geographical scope and/or the scale of weapons involved, but weapons limitations are reliant upon degrees of judgement, making them more difficult to impose or maintain. Moreover, like Mao Zedong (the Chinese leader) in 1950-1953, Kim Jong-Il is almost certainly aware of the hollow nature of the Western atomic threat. North Korea is industrialised, and may have suitable targets. But US retaliation would be condemned around the world.

Then as now, use of nuclear weapons would have wide-ranging international repercussions, arousing anti-Western feeling, and counteracting President Obama's efforts to win-over Arab and Asian opinion. Then as now, UN support would be extremely difficult (perhaps impossible) to obtain, and UN debates on the issue could prove militarily and politically advantageous to the enemy. Then as now, the atomic bomb's destructive potential operates as a self-deterrent. In short, nuclear capability still does not translate into diplomatic leverage.

Thus the answer is not to develop newer, more destructive weapons in the hope that they will deter. The answer is for the UN nations, including Russia and China, to unite in applying and maintaining stronger diplomatic sanctions. True, this could trigger the collapse of North Korea's economy. But the threat of implosion is far outweighed by the danger of allowing the DPRK to develop into a fully-fledged, hostile nuclear state.

Of course, all this assumes that some states should have nuclear weapons, while others should not. The recent Russian-American agreement to reduce the number of nuclear warheads brings us a step closer to Obama's vision of multilateral disarmament. Yet, securing and enforcing a Fissile Material Cut-Off Treaty (a ban on the production of weapons-grade plutonium and uranium) will be no easy task. Moreover, the US Senate rejected the Comprehensive Test-Ban Treaty in 1999. Without these two agreements, the President's dream of multilateral disarmament will remain just that: a dream. In the meantime, if Kim goes unpunished, other states such as Iran might follow his example or cooperate with him in their bid for nuclear arms.

Further Reading

Roger Dingman, "Atomic Diplomacy during the Korean War", International Security, Vol. 13, No. 3 (Winter, 1988-1989): 50-91

Alexander L. George, and Smoke, Richard, "Deterrence and Foreign Policy", World Politics, Vol. 41, No. 2 (January, 1989): 170-82

Morton H. Halperin, "Nuclear Weapons and Limited War", The Journal of Conflict Resolution, Vol. 5, No. 2 (June, 1961): 146-66

Robert Jervis, "Was the Cold War a Security Dilemma?", Journal of Cold War Studies, Vol. 3, No. 1 (2001): 36-60

T.V. Paul, "Nuclear Taboo and War Initiation in Regional Conflicts", The Journal of Conflict Resolution, Vol. 39, No. 4 (December, 1995): 696-717

Mark A. Ryan, Chinese Attitudes Toward Nuclear Weapons: China and the United States During the Korean War (New York, 1989)

Thomas C. Schelling, "Bargaining, Communication, and Limited War", Conflict Resolution, Vol. 1, No. 1 (March, 1957): 19-36


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