After Nagasaki, the Origins of American Nuclear Strategy

Nagasaki Atomic Bomb Museum · TAE Hee-jun · Seoul National University

Introduction

On August 6, 1945, humanity experienced its "first nuclear war" (Mandelbaum 1979, 41). This was the day the first atomic bomb was dropped on Hiroshima. Three days later, an atomic bomb also fell on Nagasaki. These two bombings resulted in over 200,000 casualties. The shock of Hiroshima and Nagasaki finally led to Japan's surrender. These events not only marked the end of World War II but also signaled the dawn of the nuclear revolution era.

The Little Boy dropped on Hiroshima, made of 64 kilograms of uranium-236, caused an explosion equivalent to 13 kilotons of TNT. Meanwhile, the Fat Man dropped on Nagasaki, using only 6.2 kilograms of plutonium-239, caused an explosion equivalent to 22 kilotons of TNT.

5 The explosive power of these two atomic bombs was equivalent to what would have required 5,000 bombers using conventional weapons at the time (E. Tashiro and J. Tashiro 1982, 32; Wilson 2013, 67).

Photograph 1. Entrance to the Nagasaki Atomic Bomb Museum. The discovery of this "new weapon of unprecedented destructive power" (Truman, 1945) heralded a new era of revolution while leaving two crucial lessons and warnings. First, humanity confirmed the danger of an "absolute weapon" (Brodie, 1946; Mueller 2010, 18) that could determine the outcome of war and be exploited as a tool of coercive diplomacy.

6 Second, it was confirmed that nuclear weapons could be used as humanity's most immoral instruments of slaughter, indiscriminately targeting both military and civilian casualties (Morris 1963, 85).

Consequently, the world began to seek institutional solutions for the prevention of nuclear proliferation and disarmament after Nagasaki. As a result, the United Nations Atomic Energy Commission (UNAEC) was established in January 1946. This was the first solution devised by the international community through a lengthy consensus process among the Soviet Union, the United States, and the United Kingdom to control nuclear weapons. However, the Atomic Energy Commission did not function effectively. Furthermore, the international community failed to agree on additional solutions thereafter (Kissinger 1957, 177-178; Price and Tannenwald 1996, 137). This was because the US and the Soviet Union began to clash over the institutional management of atomic energy. While the United States intended to monitor Soviet activities through the United Nations, the Soviet Union expected the United States to dismantle its nuclear weapons. Ultimately, the conflict over the use of atomic energy and the development of nuclear weapons led to a fundamental shift in post-war global politics.

Despite international efforts, the world became divided, led by the two superpowers, the United States and the Soviet Union. In particular, an unprecedented nuclear arms race ensued, which also brought about significant changes in the patterns of global conflict and warfare. The existence of nuclear weapons deterred all-out war and general war between the US and the Soviet Union. However, it did not prevent the outbreak of limited wars and local wars in specific regions.

7 This was because both countries, fearing a full-scale war with the other, avoided intervening in conflicts in which one was involved. Thus, with the advent of nuclear weapons in human history, the peace and security strategies that the international community had pursued since World War II began to diverge (Mandelbaum 1981, 11).

Photograph 2. The atomic bomb dropped on Nagasaki - Fat Man

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Research on the Origins of Nuclear Strategy

The topic of the "origins of nuclear strategy" is one that has not been adequately addressed in existing literature (Glaser 1990, 7). Current nuclear discourse either affirms or denies the impact of absolute weapons in ontological, teleological, or normative terms, without explaining the background from which nuclear strategy originated. Above all, discourse-centered explanations inherently have limitations, leading to divergent positions on the same concepts or theories. For instance, Jervis (1979) categorizes theories of nuclear strategy into three schools of thought. First, the "nuclear revolution theory," primarily formed by Brodie (1946; 1959), Mandelbaum (1979; 1981), and Waltz (1981; 1990). Second, the "nuclear risk manipulation, escalation, and limited war theory," which addresses the "problem of risk" among nuclear-armed states based on Snyder's (1965) "stability-instability paradox." Key theorists of this school include Schelling (1960), Kahn (1960; 1966), and Halperin (1963). Finally, the third school of thought, which includes Jervis himself, comprises scholars like Tannenwald (2007), Mueller (2010), and Wilson (2013), who have recently raised the "nuclear irrelevance theory" in debates surrounding the effects of nuclear weapons.

9 This school of thought has been consistently raised in discussions about the effects of nuclear weapons.

While these schools of thought present divergent perspectives, they all commonly start from the characteristics of nuclear weapons. The first school argues that the destructive power of nuclear weapons prevents nuclear-armed states from engaging in conflicts that could escalate to war. In other words, they believe there is a low risk of confrontation or crisis among nuclear-armed states, and nuclear proliferation would reduce the frequency of war by diminishing states' willingness to engage in conflict (Sagan and Waltz, 1995). This perspective suggests that early US nuclear strategy also originated from these characteristics of nuclear weapons.

Conversely, the second school raises concerns about the risk of confrontation among nuclear-armed states. They argue that the characteristics of nuclear weapons make them "unusable," thus diminishing the credibility of the threat of nuclear war escalation. Nevertheless, they contend that nuclear-armed states escalate conflicts and manipulate the risk of war by posing threats of preemptive strikes and preventive wars against non-nuclear states and among themselves, as well as threats of massive retaliation. The argument of this school ultimately posits that confrontations between nuclear-armed states are characterized by brinkmanship and crisis management, leading to coercive bargaining and the projection of power at the level of limited war.

10 The argument of the third school is less relevant to my research, so I will omit a detailed explanation. In essence, the consistent puzzle found in existing literature is the scarcity of research on the origins of US nuclear strategy and the existence of multiple interpretations of the same historical data and periods.

Photograph 3. Progression leading up to the atomic bombing of Nagasaki

Meanwhile, the history of nuclear strategy has been described in close relation to the history of nuclear technology and weapons development. Mandelbaum (1979), who uniquely used the expression "origins of nuclear strategy," also argued that "strategy followed technology." He posits that US nuclear strategy originated in 1953. The reasons he cites are: first, neither the US nor the Soviet Union possessed a sufficient quantity of nuclear weapons before 1953; second, there was no clear strategic intent in the production of nuclear weapons; and third, the arms race between the US and the Soviet Union truly began after 1953. Most importantly, November 1953 and August 1953 marked the dates when the United States and the Soviet Union tested hydrogen bombs, respectively. Given that hydrogen bombs were weapons with 700 times the destructive power of the atomic bombs dropped on Hiroshima, existing literature regards the development of the hydrogen bomb as a revolutionary event that "brought about a great transformation in world affairs" (Ibid.). Unlike atomic bombs, which were "produced for actual use" (Ibid.), hydrogen bombs were weapons that should not be used, and they first acquired a strategic objective of "minimum deterrence" (Kahn 1960, 15).

11 Furthermore, existing literature has highlighted the years 1957 and 1958, when the Soviet Union and the United States tested ballistic missiles, as turning points in the development of nuclear strategy. The development of ballistic missiles, a new unmanned nuclear delivery system, exposed the world to the threat of immediate nuclear attack (Brodie, 1959, 158-160). Ballistic missiles significantly reduced the time required to initiate a nuclear attack and the time to intercept targets, making nuclear attacks difficult to predict and defend against, and enabling simultaneous strikes against targets worldwide. Moreover, unlike long-range bombers, ballistic missiles were strategic weapons that were easy to conceal and protect.

12 In this regard, the nuclear and security strategies of the US and the Soviet Union faced new challenges and were revised. Existing literature has consistently referred to the development of hydrogen bombs and ballistic missiles as the "Pandora's Box" that initiated the history of nuclear strategy (Schwartz 1995, 37; Lindley-French and Boyer 2012, 500).

However, the approach of existing literature, which explains the history of nuclear strategy by linking it to the history of nuclear weapons technology, commits the error of post-hoc reconstruction of history to fit a specific criterion. That is, existing literature has identified the origins of nuclear strategy as the point in time when the conditions for "nuclear deterrence" to function—namely, the technological, military, and international political structural conditions (Glaser 1990, 19-21)—were met. In short, it has retrospectively assigned significance to individual historical events by comparing the destructive power of atomic and hydrogen bombs and the value of bombers and ballistic missiles as strategic assets.

Therefore, I propose an approach that understands the historical context in which each policy was decided, rather than the outcome-oriented explanations of existing literature. To achieve this, it is necessary to refer only to the information available to policymakers at the time of each individual event and the international situation at that time. Through meticulous primary source research, I aim to provide a detailed narrative of how history unfolded and to examine the causal relationships between observed patterns and changes over time using the process-tracing method. In other words, unlike previous approaches that explained the origins of nuclear strategy teleologically or consequentially, I sought to understand the development of nuclear strategy as a series of processes and to grasp the context in which it evolved. Ultimately, I believe the origins of nuclear strategy should be sought not in established tactics and policies, but in the circumstances that necessitated the strategy.

The Puzzle of the Truman Administration

13 In contrast to the teleological or consequential explanations of existing literature, I aimed to understand the development of nuclear strategy as a series of processes and to grasp the context in which it evolved. Ultimately, I believe the origins of nuclear strategy should be sought not in established tactics and policies, but in the circumstances that necessitated the strategy.

The Puzzle of the Truman Administration

As explained earlier, existing literature has focused on the periods of 1953-54, when the US and the Soviet Union tested hydrogen bombs, and 1957-58, when they tested ballistic missiles, in the history of nuclear strategy development. However, based on publicly available data today, I have noted a significant increase in US nuclear weapons production starting in 1951. What is particularly noteworthy is that existing approaches, which analyze the development of US nuclear deterrence strategy in conjunction with the history of nuclear weapons development, fail to explain this phenomenon. For example, even if we shift the benchmark to 1949, the year the Soviet Union successfully conducted its first atomic bomb test, as examined in Tables 1 and 2, the US nuclear weapons production and nuclear budget trends, which remained stable without significant changes in 1949 and 1950, show a sharp transition in 1951 and 1952, which is difficult to explain.

14 Tracking US nuclear weapons production trends for ten years from the post-Nagasaki period, we can confirm a significant surge in production in 1949 and 1952. The former surge can be somewhat explained in relation to the Soviet Union's successful development of nuclear weapons. However, there are no events in the history of nuclear weapons technology development that can be linked to the latter phenomenon in 1951. Notably, the transition in 1951 was a more significant event than that in 1949. At that time, the US possessed approximately 400 nuclear weapons, but the following year, it produced an additional 400, nearly doubling its stockpile compared to the previous year. While the growth rate of nuclear weapons production might have been higher in 1949, the absolute increase in nuclear weapons in a single year was overwhelmingly larger in 1952 compared to other years. This is also confirmed by examining the seven-year (1947-1954) nuclear budget trends of the US Department of Defense and the Air Force in Table 1. In summary, the nuclear weapons budgets and their growth rates for these two agencies in 1951 were overwhelmingly higher than in other years (Air Force budget: 452%, Department of Defense budget: 261%).

14 can be confirmed. The first phenomenon can be explained in relation to the Soviet Union's successful development of nuclear weapons. However, there are no events in the history of nuclear weapons technology development that can be linked to the second phenomenon in 1951. In particular, the transition in 1951 was a more significant change than that in 1949. At that time, the United States possessed around 400 nuclear weapons, but the following year it produced an additional 400, securing nearly double the previous year's inventory. While the production growth rate of nuclear weapons itself might have been higher in 1949, the absolute increase in nuclear weapons added in a single year is overwhelmingly greater in 1952 compared to other years. This fact can also be confirmed in |Table 1|, which examines the trend of the seven-year (1947-1954) nuclear budget of the U.S. Department of Defense and Air Force. In summary, the nuclear weapons budget and its growth rate in 1951 for both agencies were overwhelmingly higher than in other years (Air Force budget: 452%, Department of Defense budget: 261%).

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Photograph 4. Presentation at the Nagasaki Atomic Bomb Museum

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17 Therefore, I investigated the potential differences caused by the variable of US nuclear weapons mass production capacity during this newly identified period of re-examination. Specifically, if there were differences based on the nuclear production facilities operated in the US before and after 1951, it would be necessary to first distinguish between periods when mass production capacity was possible and when it was not. However, I confirmed that the major US nuclear production facilities, operated between 1942 and 1957, were already completed and operational before 1952. (Refer to this research paper). Furthermore, facilities added in 1952 were generally completed or began operation after September and November, making it unlikely that they were a decisive factor in the US nuclear weapons production volume in 1952. Therefore, this was not a natural phenomenon resulting from a simple difference in production capacity. In other words, the significant shift that occurred between 1950 and 1953 was likely a change brought about by US willingness.

These two facts were overlooked in existing literature and are the core puzzles I raise in my research. Therefore, I have re-examined the role of the Truman administration, which has not received attention in existing literature on US nuclear strategy. This is because the existing approach, which describes nuclear strategy based on the history of nuclear technology development, cannot explain the period of rapid change between 1950 and 1953. In other words, I sought to find the origins of nuclear strategy not in the conditions for its establishment as proposed by certain nuclear discourses, but in the most fundamental aspects.

18 I sought to find the origins of nuclear strategy in the period when the United States directly recognized the need for it, or in the historical events that formed its background.

Ultimately, the data examined above suggests that the United States first decided on the mass production of nuclear weapons between 1950 and 1951. This period is particularly interesting because it coincides with the outbreak of the Korean War. Thus, my hypothesis is that the Korean War may have had a decisive impact on the change in US threat perception that led to the origins of nuclear strategy. If so, how did the US perception of the need for nuclear strategy change during the nuclear revolution era?

The Early Origins of Nuclear Strategy: Between Nagasaki and the Korean War

During World War II, the United States optimistically viewed the post-war international order, anticipating the emergence of numerous countries advocating for a liberal democratic order worldwide. In the early to mid-1940s, the Soviet Union actively sought cooperation with the United States to counter Germany, and in the process, Stalin voluntarily dissolved the Comintern, the foundation of the communist bloc. This led to an almost blind faith in the US leadership's expectations of the Soviet Union, leading them to believe that the Soviet Union would no longer promote world revolution.

19 One of the key documents confirming the perception of the Soviet Union by the US administration at the time is the Department of State's "Statement of U.S. Foreign Policy" dated December 1, 1945. This document portrays the Soviet Union as a nation that must cooperate closely with the United States in all areas of international relations and further assesses that improving relations with the Soviet Union requires more "diligence and patience" than with any other country (The Joint Chiefs of Staff and National Policy 1945-1947, 37). Most importantly, the report concludes by describing US-Soviet relations as follows: "The mutual acts of firm and friendly trust shown to each other make possible a mutual affection stronger than friendship itself," emphasizing that "we should refrain from unilateral acts of aggression in order to minimize doubts about Soviet motives" (Ibid.).

Of course, the US did not fully trust the Soviet Union after the war. Between Nagasaki and the outbreak of the Korean War, the US, concerned about the possibility of war with the Soviet Union, took certain countermeasures. The Central Intelligence Agency's (CIA) "Office of Research and Estimate Report" (ORE) dated April 2, 1948, discusses in detail the possibility of the Soviet Union initiating a war in 1948. The report assesses that the Soviet Union possesses sufficient military capability to occupy Western Europe and the Near East in a short period, and based on the mobility of the Soviet military and the rapid coordination between its land, sea, and air forces, it concludes that the possibility of the Soviet Union initiating a general war cannot be entirely dismissed.

20 However, it concludes that the likelihood of the Soviet Union initiating a general war against the United States is very low, reasoning that the Soviet Union would seek to avoid a general war until its overall national economy stabilized and sufficient technological advancements for nuclear weapons development were achieved.

The optimistic world view of the US leadership persisted for a considerable period. In Analysis and Evaluation Reports (ORE) dated September 28, 1948, and April 6, 1950, the US anticipated that the Soviet Union's nuclear weapons development timeline would be later than the actual dates we know today. The US estimated that the Soviet Union would succeed in its first nuclear weapons test between 1950-53, and that it would possess 100 nuclear warheads by 1953 and 200 by 1954-55, but assessed this possibility as low. The US based its assessment on the point when the Soviet Union would possess 200 nuclear bombs, as it estimated that this minimum number of nuclear weapons would pose an immediate threat to national security by effectively destroying key US strategic facilities (ORE 60-48: Threats to the Security of the United States, 28 Sep. 1948; ORE 91-49: Estimate of the Effects of the Soviet Possession of the Atomic Bomb upon the Security of the United States and upon the Probabilities of Direct Soviet Military Action, 6 Apr. 1950).

This assessment is also found in reports from other government agencies during the same period. A National Security Council (NSC) report dated April 14, 1950, assesses the Soviet Union's nuclear weapons development quantities by period as follows: 10-20 in 1950, 45-90 in 1952, and re-evaluated to 200 in 1954-1955 (NSC 68: U.S. Objectives and Programs for National Security, April 14, 1950).

21 The report assesses the quantity of Soviet nuclear weapons development by period as follows: 10-20 in 1950, 45-90 in 1952, and an re-evaluation of 200 in 1954-1955 (NSC 68: U.S. Objectives and Programs for National Security, April 14, 1950).

This complacency of the Truman administration is also evident in a memorandum from the Department of State (DOS) in 1949 titled "Conclusions on Problems Related to the International Control of Atomic Energy." This document assesses the possibility of Soviet initiation of general war as follows: "The possibility of the Soviet Union initiating general war is virtually nil. At this point, Stalin, at the apex of his leadership, has no incentive to attempt reckless challenges such as territorial aggression or threats to the state. Unless the Soviet political system undergoes a fundamental change, there is no domestic political motivation for the Soviet Union to rashly initiate general war against the United States." (Policy Planning Staff of the DoS: Memorandum Draft, Formosa, 7 Aug. 1950). Moreover, as of April 25, 1950, the United States remained confident in the superiority of the US and the North Atlantic Treaty Organization (NATO), the free world bloc, over the communist bloc of China and the Soviet Union. This is confirmed in a report from the Joint Intelligence Committee of the US Embassy in the Soviet Union (Soviet Intentions).

Specific grounds for this confidence included: first, the Soviet military was divided into the Ministry of War and the Ministry of the Navy as of 1950, significantly reducing the absolute influence the Soviet leadership held over the military since the end of the war;

22 second, the Soviet Union does not possess aircraft carriers and has no experience in naval operations in the open sea, thus limiting the strategic operational range of its navy to coastal waters; and third, while some argue that the Soviet air force is developed enough to occupy continental Europe in a short period, a comprehensive assessment of its actual force assets (especially the number of atomic bombs) suggests this is unlikely and, more importantly, it cannot threaten the US mainland, making it a wishful hope (FRUS Report: Enclosure 514 - Soviet Intentions, 25 Apr. 1950).

Photo 5. Nagasaki Peace Statue

23 Ultimately, in the 1940s, American security strategy and perceptions of the Soviet Union developed with a degree of optimism, based on America's increased international influence and belief in the spread of liberal democracy. Of course, this can also be interpreted as an expression of pride and confidence in the new paradigm of international society that the United States, as the sole nuclear power at the time, envisioned, considering the historical context. However, as will be discussed later, this optimistic stance of the United States changed drastically with the outbreak of the Korean War, particularly from October 1950 when China intervened. This can be interpreted as revealing that the nuclear strategy the U.S. leadership had established immediately after the war was essentially just idealistic optimism.

The Formation Period of Nuclear Strategy: Changes in Threat Perception After the Collapse of the 38th Parallel

During the previous period, from the atomic bombing of Nagasaki to the eve of the Korean War, the U.S. perception of the threat from the Soviet Union was generally assessed as being at a level that the U.S. could manage and deter. The military had also designated 22 strategic locations for nuclear strikes against the Soviet Union and its satellite states in case of emergency (Epstein 1987, 14). However, following the unexpected outbreak of the Korean War in June 1950, and especially from October when the Chinese People's Volunteer Army intervened, there was a significant change in the U.S. perception of the threat from the global communist bloc.

24 The Korean War broke out on June 25, 1950. A week later, the U.S. National Security Council (NSC) drafted a report detailing the possibility of Soviet intervention in the Korean War. This report, written in the early stages of the war, assessed the likelihood of Soviet participation as extremely low and believed that the Soviet Union would hope for active U.S. involvement in the Korean War. The expectation was that if the U.S. unnecessarily depleted its military strength in conducting the war, it would ultimately lead to a reduction of U.S. influence in the Asia-Pacific region (NSC 73: Draft Estimate Possible Further Danger Points in the Light of the Korean Situation, 1 Jul. 1950).

Photo 6. In front of the memorial for Korean victims of the Nagasaki atomic bombing

25 Conversely, the U.S. adopted a cautious stance regarding the possibility of Soviet aggression in areas outside the Korean Peninsula, such as Europe. A report dated July 27 stated that if the Soviet Union invaded Europe, the U.S. would immediately implement the 'General War Plan' and would decisively utilize nuclear forces without hesitation if the moment came to use nuclear weapons to repel the enemy (NSC 73: Draft. The Position and Actions of the U.S. with Respect to Possible Further Soviet Moves in the Light of the Korean Situation, July 27, 1950).

With this confidence, three memoranda were drafted by the Policy Planning Staff (PPS) of the Department of State in July and August 1950. The first memorandum, dated July 10, argued that if Soviet forces entered the Korean War, there would be no need to initiate a world war in the Korean Peninsula, which was likely to become a war of attrition, and thus recommended immediate withdrawal and preparation for war according to the General War Plan (PPS: Memorandum - U.S. Courses of Action in the Event Soviet Forces Enter Korean Hostilities, 11 Jul. 1950). Subsequently, a memorandum dated July 24 expressed skepticism about the possibility of an inevitable confrontation with the Soviet Union escalating into a general war, let alone a world war. Most notably, a memorandum dated August 18 predicted that the Soviet leadership would ultimately choose a path of compromise for the sake of peace and survival (PPS: Memorandum - NSC 76-U.S.

26 Courses of Action in the Event Soviet Forces Enter Korean Hostilities 24 Jul. 1950).

Up to this point, it appears that the U.S. expected that even if a war with the Soviet Union were unavoidable, the U.S. would gain the upper hand, leading to victory, or that the war would not escalate into a general or world war, concluding with peaceful negotiations. Furthermore, the absence of any mention of Soviet nuclear weapons or their potential use in war in these memoranda suggests that the U.S. did not take the Soviet nuclear arsenal and operational capabilities seriously.

This perception is also evident in a letter sent by George Kennan to the State Department on August 8, 1950. He wrote that not only was the possibility of Soviet intervention in the Korean War low, but also that the U.S. held a military advantage over the Soviet Union, giving a 50% probability of Chinese intervention. Meanwhile, even about two months after the outbreak of the Korean War, by early September, the U.S. still assessed the possibility of the Chinese People's Volunteer Army's intervention as low. While acknowledging that unforeseen circumstances could not be entirely ruled out, the U.S. expressed considerable skepticism about the likelihood of China making the bold decision to intervene to aid North Korea. It was analyzed that it would not be easy for the People's Republic of China, which had not yet been established for a year, to make a decision to intervene that could cause domestic political turmoil (NSC 81: U.S. Courses of Action with Respect to Korea, 1 Sep. 1950).

27 not be easy.

However, the U.S. position, which had held such optimistic projections regarding the potential intervention of the Soviet Union and China in the Korean War, began to change rapidly from late September 1950. In a National Security Council (NSC) report dated September 21, the U.S. detailed the construction of airfields and supply routes for war preparation by the Soviet Union in strategic locations within its satellite states. Notably, the U.S. perceived the potential impact of a Soviet war initiation as significantly higher than that of the Korean War (NSC 68/1: U.S. Objectives and Programs for National Security, 30 Sep. 1950). This suggests that the U.S. threat perception towards the Soviet Union had increased compared to the pre-war period. Furthermore, unlike the pre-1950 period where the U.S. response to a Soviet war was general war, this report repeatedly emphasized that under no circumstances should the U.S. engage in war directly with the Soviet Union (NSC 68/1: U.S. Objectives and Programs for National Security, 21 Sep. 1950).

Similar threat perceptions are confirmed through other documents. According to a Policy Planning Staff (PPS) document of the Department of State dated October 11, 1950, the U.S. emphasized that it 'will not begin negotiations with the Soviet Union unless its military strength is enhanced from the current level,' acknowledging that a general confrontation with the Soviet Union could be burdensome even for the U.S. Subsequently, two reports published in November

28 mention the intervention of Chinese forces, but reveal that the U.S. was still struggling to ascertain China's intentions. Furthermore, the fact that the U.S. threat perception towards the Soviet Union and China had heightened even more than during the post-war period is clearly evident in a report dated November 15. In this report, the U.S. expressed considerable doubt about its ability to withstand an attack if Chinese forces and Soviet air power were sustained for 12 months and a war with the Soviet Union occurred. Specifically, the report reiterated that if the Soviet Union sought to expand its influence in the Korean Peninsula and the Asia-Pacific region, even at the risk of a world war, the U.S. would consider an 'honorable withdrawal from Korea' in the near future (NSC 81: Draft. U.S. Courses of Action with Respect to Korea, 4 Dec. 1950).

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Photo 7. Inside the Nagasaki Atomic Bomb Museum. Most importantly, a Policy Planning Staff (PPS) document dated January 16, 1951, indicates that the optimistic expectations the U.S. had shown from the atomic bombing of Nagasaki up to the period before China's intervention in the Korean War, and its confidence in its military superiority, had resulted in the opposite outcome. Instead, the U.S. was seriously concerned about a war with the Soviet Union and predicted that in an extreme situation, the U.S. and the Western bloc, including NATO, would struggle to counter the Soviet Union (and China) in the event of a general war. More specifically, the document states the following two points:

First, 'The only way for the Free World to avoid war with the Soviet Union is to surrender or to force the Soviet Union to abandon its expansionist goals based on relative power. Currently, the situation is unfavorable for initiating a war not only for the Soviet Union but also for the United States and its allies. The situation will likely remain the same in the future, but the gap in national power with competitors will narrow due to the development of new weapon systems. If the Soviet Union's military capabilities continue to advance, there is a high probability of a Third World War.'

30 Second, 'Therefore, the United States must break the Soviet Union's will through means other than war. That is, to deter the Soviet Union from freely using force due to fear of the consequences of its actions. The economic sanctions that the Western bloc has imposed thus far are insufficient to deter a war with the Soviet Union' (PPS: Draft, Frustrating the Design, 16 Jan. 1951).

Notably, the U.S. approached the Soviet Union's nuclear capabilities and the possibility of war initiation with a much more cautious attitude compared to the pre-war period. This was based on the recognition that the U.S. and NATO, as adversaries to the Soviet Union, had limitations comparable to, or even exceeding, those of the Soviet Union at that time. Another source illustrating this point is as follows: On February 1, 1951, the Policy Planning Staff (PPS) argued that Western European countries lacked the capacity to counter the Soviet Union on their own and that a defensive line centered around Yugoslavia and the Balkan Peninsula was necessary to prevent the spread of Soviet influence into Western Europe and North Africa. This argument reflected the U.S. threat perception of a potential Soviet invasion of Yugoslavia within two to three years (PPS: Draft, Course of Action to Meet the Threat of Soviet Action in the Spring of 1951, 1 Feb. 1951).

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Thus, after the outbreak of the Korean War, the U.S. evaluated its own military capabilities quite objectively while significantly elevating its assessment of the Soviet Union's nuclear strategy and nuclear weapons operational capabilities compared to the pre-war period. In other words, the U.S. came to perceive the Soviet Union's imminent catching up in nuclear capabilities as a serious national threat. Furthermore, as mentioned above, the U.S. emphasized the necessity of overwhelming military superiority over the Soviet Union to secure its own security. A Policy Planning Staff (PPS) memorandum dated February 2, 1951, discussing diplomatic policy towards the Soviet Union, also projected that the U.S. nuclear monopoly would be broken and that by mid-1952, the Soviet Union would possess nuclear weapons capable of neutralizing and even destroying Western countries (PPS: Memorandum - A National Strategy for the Soviet Union, 2 Feb. 1951).

Additionally, another memorandum dated April 25 warned that although the Soviet Union appeared to be avoiding conflict with the Free World, it was in fact highly motivated to increase its national power, even at the risk of war. Therefore, it emphasized that the effective deterrence against a Soviet challenge of general war lay in the military buildup of the Free World and the resulting gap in military capabilities between the two blocs, thus necessitating the desperate acquisition of military strength for the Free World to resist the communist bloc. Above all, the U.S. explained that the only effective deterrent mechanism was the possibility of U.S. nuclear retaliation if the Soviet Union were to invade the European continent (PPS: Embassy Dispatch 626, Embassy Estimate of Soviet Intentions to the Department of State from Moscow, 25 Apr. 1951).

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Conclusion: The Origins of U.S. Nuclear Strategy

The cause of the phenomenon of mass production of nuclear weapons during the Truman administration (1951-1953) is ultimately found not in the history of U.S.-Soviet nuclear weapons development, but in the history of the Korean Peninsula. Immediately after the withdrawal of U.S. forces from the Korean Peninsula in 1949, the Korean War broke out, an entirely unexpected variable for the U.S. Moreover, the second unexpected variable for the U.S. was the intervention of the Chinese People's Volunteer Army, which led to the Korean War becoming a war of attrition due to the U.S. struggling in Korea. Faced with these two variables, the U.S. perception of the threat from the Soviet Union underwent a drastic change, and the U.S. itself came to recognize its situation in Korea as a national crisis.

A notable aspect of my research is that the U.S. perception of the threat from the Soviet Union changed in a way that differs from general expectations. Specifically, the U.S. began to perceive the Soviet Union as a significant threat not from the time of the Soviet atomic or hydrogen bomb tests, but from the period after the Chinese People's Volunteer Army intervened in the Korean War. Consequently, faced with the aforementioned unexpected variables, the U.S. thoroughly and objectively reviewed its crisis management capabilities, which it had previously assessed optimistically.

33 In short, until April 1950, just before the outbreak of the Korean War, the U.S. did not consider the Soviet Union a tangible nuclear threat and even estimated that the threat of Soviet nuclear weapons would arrive around 1955 (ORE 91-49: Estimate of the Effects of the Soviet Possession of the Atomic Bomb upon the Probabilities of Direct Soviet Military Action, 6 Apr. 1950). However, this optimistic U.S. stance was no longer evident by November of the same year, immediately after the Chinese intervention in the war. A Central Intelligence Agency (CIA) report at the time not only provided an exact number for the Soviet nuclear arsenal but also projected the threat of the Soviet Union soon acquiring the capability to equip missiles with nuclear warheads, and most importantly, the risk of a precarious standoff between the U.S. and the Soviet Union within two years (NIE-3: Soviet Capabilities and Intentions, 15 Nov. 1950).

Therefore, despite the U.S. being confident in its continued absolute superiority in nuclear capabilities over the Soviet Union, it ultimately rejected the use of nuclear weapons in Korea after extensive discussion. For example, a report from the Joint Chiefs of Staff (JCS) dated March 24, 1953, still highly evaluated the positive outcomes of using nuclear weapons in Korea. It argued that it could 'more effectively, quickly, and cheaply eliminate the threat posed to UN forces in Korea, globally deter the Soviet nuclear threat, and

34 negatively impact Sino-Soviet relations if the Soviet Union neglected to support China after a U.S. nuclear attack.'

Conversely, the National Security Council NCS-147 report dated April 15 made a decision contrary to the military's opinion by emphasizing the negative effects of using nuclear weapons in Korea (Report by the Joint Strategic Plans Committee to the JCS, 24 Mar. 1953). The rationale for this decision was that if the use of nuclear weapons did not lead to military victory, it would rather diminish the deterrent function of nuclear weapons. Specifically, the U.S. worried about a shortage of nuclear weapons available for use in global security strategy if nuclear weapons were used in Korea. In other words, the U.S. feared an unavoidable general conflict with the Soviet Union if its nuclear arsenal was insufficient (NSC-147: Analysis of Possible Courses of Action in Korea, 15 Apr. 1953).

Thus, two variables from the Korean War can be seen as influencing the Truman administration's decision to mass-produce nuclear weapons. As the U.S. perception of the threat from the Sino-Soviet communist bloc changed during the Korean War, the U.S. sought to ensure the security of itself and the global Free World through the mass production of nuclear weapons. Therefore, the Truman administration's policy decision to mass-produce nuclear weapons should be seen as originating from the tactical objectives of early U.S. nuclear strategy.

The reason this study sought to retrace the origins of U.S. nuclear strategy is not simply because related discussions have not been adequately addressed in academia. Rather, it is because, despite extensive research on nuclear strategy, no one has properly grasped its origins, and more importantly, because no one has questioned the fact that the development history of nuclear weapons alone cannot explain the anomaly of 1951.

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My new historical interpretation of the origins of U.S. nuclear strategy leaves room for supplementing the limitations of existing literature. In this way, I have re-examined the role of the Truman administration in the development history of nuclear strategy.

Photo 8. Exit of the Nagasaki Atomic Bomb Museum

36 Bibliography 1. Primary Sources

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40 Katzenstein, Peter. (1996). The Culture of National Security: Norms and Identity in World Politics. (New York: Columbia University Press.) Kissinger, Henry A. (1957). Nuclear Weapons and Foreign Policy. (New York: Norton & Company.)

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43 Trachtenberg, Marc. 1989. "A "Wasting Asset": American Strategy and the Shifting Nuclear Balance, 1949-1954." International Security. Vol. 13(3). pp. 5-49.

Wilson, Ward. (2007). "The Winning Weapon?: Rethinking Nuclear Weapons in Light of Hiroshima." International Security. Vol. 31(4). pp. 162-179.

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