Answer:
WW1 and WW2 failed to resolve key issues and created resentments between countries.
Tensions between the United States and its unlikely ally in the Soviet Union persisted throughout World War II. Western Allied leaders did not forget the initial nonaggression pact made between Soviet Premier Joseph Stalin and Adolf Hitler in 1939. However, Germany’s invasion of the Soviet Union and Japan’s attack on Pearl Harbor created an alliance between the United States and the USSR. As World War II transformed both the United States and the USSR, turning the nations into formidable world powers, competition between the two increased. Following the defeat of the Axis powers, an ideological and political rivalry between the United States and the USSR gave way to the start of the Cold War. The subsequent race for superior military power sparked an era of espionage, wars over the spread of communism, and a build-up of nuclear arms that threatened global annihilation.
While President Roosevelt hoped to see a lasting peace emerge in the postwar world order, relations with the Soviet Union complicated that vision. Ever since the Bolshevik Revolution in 1917, in which the Russian monarchy fell to Soviet forces, the spread of communism beyond Russia remained a persistent fear throughout the twentieth century. This fear was not unfounded, as Soviet leaders actively sought to infiltrate or target nations to advance the global influence of the USSR. Soviet efforts to claim territory in Europe following Germany’s defeat fed into the belief that the USSR intended to expand communism across Europe.
By 1947, the United States adopted a policy of containment to restrict Soviet global power. This became a defining element of foreign policy in President Harry Truman’s administration. Outlined in a speech delivered to Congress, what became the Truman Doctrine was an open promise of US support to any country threatened by the Soviet Union. This promise lasted throughout Truman’s time in office and continued in the administrations that followed. The policy of containment later informed the “domino theory,” which stated that one country falling to Communism meant the surrounding countries were likely to fall as well. This policy ultimately pushed the United States to enter into wars in Korea, Vietnam, and other Cold War conflicts.
Mutual efforts to undermine their foe pushed the United States and the Soviet governments to plant spies within both the USSR and the United States to subvert policy, spy on intelligence, and seek out ways to hinder any effort at growing global power. While popular images of Cold War-era spies feature high-stakes missions, assassinations, and hidden recording devices that call to mind the world of characters like James Bond, these images were pulled from real-life acts of espionage. Many such gadgets, including poisoned pellets hidden in umbrellas or guns disguised as tubes of lipstick, emerged in the 1950s and 1960s. However, from the outset of the Cold War, acts of espionage between the United States and the USSR already existed.
Soviet espionage initially centered on stealing information related to the development of nuclear weapons. The Trinity test, in which the United States detonated a nuclear weapon for the first time, along with the use of two atomic bombs subsequently dropped on Japan, sent a clear message to the world that the United States held the most powerful bombs on earth. This gave the United States an undeniable advantage over other nations, and the USSR moved quickly to develop their own nuclear technology. Initially unsuccessful, the Soviets embedded spies in the United States to steal military secrets, including vital information that helped the USSR build and test their own nuclear bomb in 1949, only four years after the Trinity test. One of the most critical Soviet spies was Klaus Fuchs, a leading physicist who worked on the Manhattan Project and was a member of the Communist Party. After the Soviets tested their first nuclear bomb, the US Federal Bureau of Investigation (FBI) identified Fuchs as the Soviet source. Questioned in December 1949, Fuchs confessed to the deed. Another spy who worked on the Manhattan Project, Theodore Hall, stated he volunteered to pass information to the Soviets in order to equalize the global playing field. Unlike Fuchs and other Soviet spies captured by the FBI, Hall was able to evade US authorities and never went on trial.