Cold War (1945–1950), the Start of the Atomic Age

Cold War (1945–1950), the Start of the Atomic Age


The Cold War was an ideological, political, economic, and military conflict between the United States and the Union of Soviet Socialist Republics (U.S.S.R.), which began in the aftermath of World War II and ended in 1989. From the outset, the Cold War was inextricably linked with the development of the atomic bomb and its use as a military deterrent.

Roots of the Cold War. The enmity between the United States and Russia, the largest of the fifteen republics that ultimately constituted the U.S.S.R., stemmed from a long history of mutual distrust. Opposing plans concerning the political and economic future of post-World War II Europe and disputes concerning the development and control of atomic weapons intensified the conflict. The seeds of antagonism date back to 1917. That year, the United States dispatched a contingent of soldiers to assist European allies in overthrowing Russia's new communist regime, which had come to power during the Russian Revolution. Despite the operation's failure, the U.S. government continued to deny the new Soviet Union diplomatic recognition until 1933. After a brief period of cooperation, Russian leaders' suspicions toward America began anew at the dawn of World War II. They considered Western nations' initial refusal to oppose Nazi Germany and Japan with arms part of a capitalist scheme to destroy the U.S.S.R. Americans, on the other hand, assumed that the brutal regime of Soviet dictator Joseph Stalin (1879–1953) was only slightly better than that of Germany's leader Adolph Hitler (1889–1945).

During World War II, Stalin's doubts about the sincerity of American vows to support the Soviet war effort intensified. Soon after the beginning of the war in 1939,

Melita Norwood, an 87-year-old great-grandmother, reads a statement outside her London home after being unmasked as one of the Soviet Union's top Cold War spies who passed atomic secrets to Moscow, giving the Soviet Union a vital edge in the arms race. ©REUTERS NEWMEDIA INC./CORBIS.
Melita Norwood, an 87-year-old great-grandmother, reads a statement outside her London home after being unmasked as one of the Soviet Union's top Cold War spies who passed atomic secrets to Moscow, giving the Soviet Union a vital edge in the arms race. ©

the Soviet Union bore the brunt of military action, attempting to fend off a massive German invasion. Although American President Franklin D. Roosevelt (1882–1945) promised the Soviet leader substantial economic aid, the United States managed to provide relatively few supplies. More important, Roosevelt assured Stalin in 1942 that American troops would relieve some of the military pressure on Russia by establishing a second front in Western Europe. However, logistical and production problems postponed an allied invasion for several years. When allied forces finally landed on Europe's shores on June 6, 1944, Roosevelt had reneged on his promise three times. This delay burdened post-World War II U.S.-Soviet relations considerably.

Even before Germany's surrender on May 9, 1945, additional disputes arose over the future of liberated Europe. The United States envisioned democratic and freely elected societies based on the right of self-determination and free trade. By contrast, the Soviet Union sought territorial expansion and spheres of influence that would guarantee the country's national security. Accordingly, during and after the war, Stalin insisted on establishing Eastern European governments supportive of the Soviet Union. He considered countries such as Poland, Bulgaria, and Romania part of an essential buffer zone to prevent future attacks on the territory of the U.S.S.R. However, this demand was the exact opposite of President Roosevelt's vision of self-determination. These disagreements were aggravated by the U.S. government's decision to provide economic aid with the stipulation that Stalin revoke his adamant stance on the territorial question.

Beginning of the Atomic Age. The atomic bomb became the final divisive issue, contributing to the ultimate breakdown of U.S.-Soviet relations. In late 1938, German physicists had discovered that uranium atoms undergo fission when bombarded by neutrons. They found that this fission triggered a self-sustaining atomic reaction that could release enormous amounts of energy. Their discovery had significant potential for the development of a powerful new weapon. In 1939, a group of European émigré scientists in the United States verified the possibility of a nuclear chain reaction. The group's leader, Hungarian physicist Leo Szilard (1898–1964), worried that Nazi Germany might use this knowledge to develop an atomic bomb. In August 1939, Szillard asked famous physicist Albert Einstein (1879–1955) to sign a warning letter to President Roosevelt to convince him of the necessity to forestall German scientists. But only in early 1942 did the U.S. government finally launch an official research project to develop the new weapon.

In what the United States Army code-named Manhattan Engineer District (later dubbed Manhattan Project) scientific director J. Robert Oppenheimer (1904–1967) assembled a team of American and British scientists and engineers who developed two weapon designs. One relied on the rare Uranium-235. The other, more complicated, design used man-made Plutonium-239, which was produced in nuclear reactors that University of Chicago physicist Enrico Fermi (1901–1954) had invented in 1942. By 1944, three large reactors produced uranium and plutonium for the first American bombs. On July 16, 1945, Manhattan Project scientists tested the Plutonium weapon near Alamogordo, New Mexico, setting off the world's first nuclear explosion.

The decision by President Roosevelt's successor Harry S. Truman (1884–1972) to use atomic bombs in the military conflict with Japan proved the destructive power of nuclear weapons to the world. On August 6, 1945, a B-29 aircraft dropped a Uranium bomb over Hiroshima, Japan, obliterating the city and instantly killing 100,000 civilians. Three days later, a Plutonium bomb killed another 30,000 Japanese citizens at Nagasaki. On August 14, 1945, Japan finally surrendered. Thus, the last chapter of World War II marked the beginning of the atomic age.

The nuclear attack on Japan and the secrecy that surrounded the development of the bomb increased the tensions between the United States and the U.S.S.R. Neither President Roosevelt nor Truman was willing to share information on the bomb with the Soviets. American scientists' appeals to inform Stalin of the new research were ignored. Rather, President Truman sought to use his country's atomic monopoly as leverage in the worsening conflict. Soviet scientists had already learned of the Manhattan Project during World War II through espionage, however, and were now coordinating their own research project on nuclear weapons. They used detailed plans that Soviet spies had supplied them. German-born physicist Klaus Fuchs (1911–1988) in particular provided crucial intelligence that facilitated the acquisition of the atomic bomb by the Soviet Union. As early as 1941, when working on Great Britain's nuclear program, Fuchs began to relay classified information to Russia. Later working on the Manhattan Project, he provided Soviet scientists with facts on virtually every aspect of the project's research. When the U.S.S.R. finally tested its own atom bomb on August 29, 1949, Stalin's scientists detonated a near-perfect replica of the American Plutonium weapon.

During the period between the first nuclear explosion in New Mexico and the end of America's atomic monopoly, a series of divisive events and decisions gradually established the fronts of the Cold War. The year 1946 saw increasingly belligerent language on both sides. Joseph Stalin proclaimed in early February that a new war was inevitable as long as capitalism existed. That same month, Moscow-based foreign-service officer George Kennan suggested in a secret telegram to Washington that the Soviet Union sought to expand its influence and planned to defeat its Western rivals. He argued that only long-term attentive containment of these expansive tendencies would avert disaster. Echoing Kennan's concerns in March, British Prime Minister Winston Churchill (1874–1965) warned of an "iron curtain," with which the U.S.S.R. would shackle Eastern Europe. Churchill also argued that the West needed to resist Communist expansion. Later that year, the Soviet Union provoked a major crisis when it continued to occupy Iran despite an agreement with Great Britain to leave the country after six months of post-war occupation. Threatened with military confrontation, Soviet troops eventually withdrew, but the Iran crisis further strained U.S.-Soviet relations.

The debate on the international control of atomic energy clearly reflected the increasing animosity between the two nations. The final U.S. plan that the administration's representative Bernard Baruch (1870–1965) presented to the United Nations on June 14, 1946, proposed to create an international agency that would supervise the mining of uranium and the manufacture of plutonium. Baruch's scheme encouraged nations to conduct research on the atom's peaceful use, but insisted on the American atomic monopoly. The Soviet Union rejected the plan. When U.S. scientists conducted a new series of nuclear weapon tests at the Bikini Atoll in the South Pacific in the summer of 1946, Stalin denounced it as proof of America's insincerity about international control.

In 1947, President Truman demonstrated that the Cold War already dominated American foreign policy. Early that year, concerns increased that Greece and Turkey might soon come under communist domination. In what came to be known as the Truman Doctrine, the American president asked Congress on March 12, 1947, to authorize economic and military aid for the two nations to prevent a communist take-over. According to Truman, this was a litmus test of the willingness of the United States to stop the spread of communism everywhere in the world. Couching the conflict in ideological and moral terms, Truman proclaimed that people would have to choose between the alternatives of communist tyranny and democratic freedom. After Truman's impassioned speech, the requested aid package passed Congress easily. The Truman Doctrine prompted most Americans to view the conflict with the U.S.S.R. as a primarily ideological struggle between binary opposites of good and evil.

United States national security policy during the Truman administration revolved, however, around more than ideology. In the eyes of Washington's policy makers, American predominance depended on power, which they defined as the control of resources, industrial infrastructure, and strategic superiority. The National Security Council (NSC) and the Central Intelligence Agency (CIA), created by the National Security Act of 1947, used the same criteria when assessing potential Communist threats and American vital interests. The NSC served as a crucial strategic planning body for security policy. The CIA continued the espionage work of the wartime Office of Strategic Services (OSS). In 1950, a planning document drafted by the NSC, NSC-68, predicted an indefinite period of conflict with the Soviet Union, calling for a vast American military buildup. In the ensuing years, NSC-68 became the basis for American Cold War strategy.

Ideological premises and geostrategic security concerns were inextricably linked with American economic interests. Becoming one the most important initiatives of the early Cold War, the Marshall Plan of 1947 served these economic interests and finalized the division of the world into two hostile camps. Drawn up by secretary of state George Marshall (1880–1959), the plan launched a massive economic aid package for the reconstruction of Western Europe. Healthy capitalist economies, Marshall argued, would provide American companies with new markets and could help weld European nations into an effective bulwark against Communism.

Although the United States invited the Soviet Union and Eastern European countries to apply for economic aid as well, negotiations soon demonstrated that Stalin would never accept the American plan. In fact, the Marshall Plan would not only allow the United States to control the distribution of aid, but would also give them access to the Soviet Union's economic records. Predictably, Stalin withdrew from the negotiations and countered the American economic aid project with the Molotov Plan, a series of bilateral trade agreements with Eastern European countries. The Soviet plan transformed these countries into a Communist counter alliance against the West.

In another confrontation, Stalin attempted to force the United States, Great Britain, and France to revoke their decision to unify their three occupation zones in Germany. On July 23, 1948, the Soviet dictator initiated a year-long blockade of all supplies to the city of Berlin in the Russian zone. The United States responded with a well-organized air lift, which supplied the encircled city for almost one year. In the end, the air lift forced Stalin to give up the blockade. By that time, however, the Soviet Union already dominated Eastern Europe. In February, 1948, Czech and Slovak communists had toppled Czechoslovakia's democratic government and established a pro-Soviet Communist regime, adding the country to the Soviet bloc. In Hungary, Stalin also had imposed Communist rule. When the western part of Germany constituted itself as the Federal Republic of Germany in spring of 1949, the U.S.S.R. initiated the permanent division of the country by establishing the German Democratic Republic in the former Russian occupation zone. On April 4, 1949, the United States, Canada, and ten Western European nations had reacted to Soviet hostilities forming the North Atlantic Treaty Organization (NATO), a military alliance designed to protect its members against a potential Soviet attack.

Thus, by 1950, the framework of the Cold War was firmly in place, prompting both sides to enhance their military capabilities, in particular their nuclear arsenal. By the beginning of the new decade, the United States had amassed three hundred nuclear weapons. However, since the American administration had learned in early September, 1949, that the Soviet Union had successfully tested an atomic bomb, American policy makers considered that the strategic superiority of the United States might be in jeopardy. As a result, President Truman ordered American scientists to develop a weapon that was even more powerful: the hydrogen bomb. By the mid-1950s, both nations had developed and tested this new weapon, marking the beginning of a new round of Cold War confrontations.



Carlisle, Rodney P., with Joan M. Zenzen. Supplying the Nuclear Arsenal: American Production Reactors, 1942–1992. Baltimore: John Hopkins University Press, 1996.

Gaddis, John L. The United States and the Origins of the Cold War. rev. ed. New York: Columbia University Press, 2000.

——. We Now Know: Rethinking Cold War History. New York: Oxford University Press, 1997.

Herken, Gregg. Cardinal Choices: Presidential Science Advising from the Atom Bomb to SDI. rev. and exp. ed. Stanford, CA: Stanford University Press 2000.

Holloway, David. Stalin and the Bomb: The Soviet Union and Atomic Energy, 1939–1954. New Haven, CT.: Yale University Press, 1994.

Leffler, Melvyn P. A Preponderance of Power: National Security, the Truman Administration, and the Cold War. Stanford, CA: Stanford University Press, 1992.

Roleff, Tamara. ed. The Atom Bomb. San Diego, CA: Greenhaven Press, 2000.


Berlin Airlift
CIA (United States Central Intelligence Agency)
National Security Act (1947)
NATO (North Atlantic Treaty Organization)
NSC (National Security Council)
Nuclear Reactors
OSS (United States Office of Strategic Services)
Truman Administration (1945–1953), United States National Security Policy
United States, Intelligence and Security

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