The years after World War II marked a unique era in American history, one characterized by increased economic prosperity and a great expansion of the role played by the United States in world affairs. But all that glittered was not gold. Shortly after the end of the war, relations between the United States and its former ally the Soviet Union took a dramatic turn for the worse. The Cold War, as it came to be known, pitted the capitalist, democratic Western powers against the communist regime of the Soviet Union and its eastern European client states. Although the United States and the Soviet Union never directly engaged in hostilities, they did come near to blows on several occasions and participated in various proxy wars in later decades. The Cold War, as threatening as it was, was made all the more dangerous by the presence of nuclear weapons on both sides.

The years after World War II marked a unique era in American history, one characterized by increased economic prosperity and a great expansion of the role played by the United States in world affairs. But all that glittered was not gold. Shortly after the end of the war, relations between the United States and its former ally the Soviet Union took a dramatic turn for the worse. The Cold War, as it came to be known, pitted the capitalist, democratic Western powers against the communist regime of the Soviet Union and its eastern European client states. Although the United States and the Soviet Union never directly engaged in hostilities, they did come near to blows on several occasions and participated in various proxy wars in later decades. The Cold War, as threatening as it was, was made all the more dangerous by the presence of nuclear weapons on both sides.

The establishment of the United Nations in 1945 brought hope that a new and better world would emerge from the ashes of World War II. A charter member of the new international body, which was headquartered in New York, the United States was expected to play a leading role in the institution. Unlike the situation after World War I, when the US Congress refused to join the League of Nations, this time, a bipartisan Senate majority backed the idea. The tradition of isolationism seemed to have been broken. It was thought that the permanent members of the UN’s all-important Security Council, consisting of the great powers from the postwar period (the Soviet Union, the United Kingdom, France, China, and the United States), would work in concert to serve as a police enforcer in the world, maintaining the peace among the smaller nations.

There were internal divisions within the United States government, of course. Some in the administration of President Harry S. Truman wished immediately to expand US power, intending to make use of the nuclear diplomacy at the 1945 Potsdam Conference (involving the United States, Britain, and the Soviet Union) to do so. At that point, only the Americans had the atom bomb. But other forces in Washington countermanded this prospect. Secretary of State James F. Byrnes, for one, let it be known at foreign ministers conferences in London and Moscow that the United States would silently accept Soviet-sponsored governments in eastern Europe. Thus, through much of 1946 US policy officials continued to treat the Soviet Union with kid gloves rather than assert US nuclear superiority.

And the Soviet Union took advantage of the situation. It pursued expansionist aims in Iran, made inroads into the Mediterranean, and solidified its grip on eastern Europe. US reactions to such advances started to become more oppositional. Though he did not coin the phrase, Winston Churchill spoke in Fulton, Missouri, about an “Iron Curtain” descending in Europe, dividing East from West, and by late 1946 many US lawmakers agreed. Central to the turnaround was the work of George F. Kennan, an American embassy official in Moscow, who, in a detailed policy memorandum from 1946 and subsequent writings, prescribed the strategy of “containment” with respect to the Soviets. Kennan argued for a firm hand in controlling the spread of communism, primarily by reacting immediately to Soviet forays abroad.

It was on this basis that President Truman announced his Truman Doctrine in March 1947, which drew on the concept of containment. The doctrine stated that the United States was compelled to assist, both economically and militarily, “free peoples” who were working to resist subjugation by totalitarian regimes. The cases-in-point at the time were the Greeks and the Turks, both of whom faced struggles that could, Truman noted, result in communist advances. In each case, therefore, support should be given to anticommunist elements in these countries, both to bolster democracy and to limit Soviet influence.

In Europe the postwar reconstruction plan known as the Marshall Plan (after its chief proponent, George Marshall) became another reflection of the Truman Doctrine. Announced in mid-1947 and launched in earnest a year later, the plan called for assistance on a grand scale ($13 billion) to war-torn areas of western Europe, which otherwise stood to become breeding grounds for communism. Soviet leaders fought the plan’s implementation tooth-and-nail, but to no avail. In Germany, by 1948 the three Western occupying powers (France, Britain, and the United States) had consolidated their separate control zones, causing the Soviets to respond with a blockade of Berlin. The Americans and British responded, in turn, by establishing an airlift to supply the city with food and other goods and to bring out its exports. After 11 months the Russians, facing the reality of the situation, removed the blockade. In the end, the Marshall Plan showed itself to be a significant intervention that both helped western European economies and spread American ideas, influence, and culture throughout the region.

In Japan, too, a large-scale occupation and rebuilding effort got under way behind American leadership. A new democratic constitution, which barred the development of a permanent military, went into effect in 1947. American culture and ideas took hold in various areas of society, above all in industrial production. New technologies and production methods yielded significant economic benefits, eventually turning Japan into an Asian powerhouse. In China, on the other hand, American efforts to support General Chiang Kai-shek and his Nationalists against Chinese communist forces failed, and in 1949 Chiang was relegated to the island of Formosa (Taiwan). Hard-line anticommunists in the United States began searching for State Department officials to blame for the “loss” of China.

In April 1949 the United States, along with 11 other powers, entered into the North Atlantic Treaty Organization (NATO). This treaty capped the move away from isolationism, as it represented the first time in nearly 150 years that the United States was in a peacetime military alliance with a European power. Additional broad-based treaties linked nations in the Americas together in a mutual assistance pact—an extension of the Monroe Doctrine, as far as the United States was concerned. This solidifying of Cold War camps, communist versus capitalist, was viewed as the inevitable outcome under the circumstances. It provided a context when, in August 1949, the Soviet Union conducted its first atomic bomb test. Leaders around the globe began to concern themselves with the control of nuclear weapons. Meanwhile, the United States ramped up its own production of such weapons (and developed more deadly versions of them), as did military leaders in Moscow. The arms race was under way.

The Cold War influenced domestic affairs profoundly, as political opponents of the Truman administration sought to attach blame for the rise of the communist threat. As a result, Truman achieved fewer of his goals in areas such as civil rights than he had hoped to. The end of the war was followed by a rapid demobilization of the armed forces, but it also brought shortages in housing, an inflationary trend in the economy, conflicts between labor and management, and the emergence of a new “red scare” wherein innocent citizens and government officials alike were persecuted for their alleged ties to communist organizations. Those who actually professed left-leaning politics were essentially forced underground.

Truman himself, no friend of communism, gave impetus to the red scare—partly to forestall his critics. In March 1947 he established a Federal Employees Loyalty and Security Program in order to examine the backgrounds of the 4 million-plus workers in the federal government and dismiss those deemed to be “disloyal” (a vaguely defined concept). Those accused of disloyalty, or of belonging to any one of a list of supposedly subversive organizations, had no legal recourse. With the cooperation of the House Un-American Activities Committee (HUAC), thousands were investigated, nearly 400 were discharged, and close to 2,500 resigned—despite the fact that hard evidence of espionage was largely absent. (In one notable case, that of Alger Hiss, a perjury charge was later proved.) The effort helped Truman get reelected in 1948. HUAC continued its pursuits into the early 1950s, gaining notoriety when it attacked Hollywood screenwriters and directors for their alleged radical sympathies. Eventually, the committee was overshadowed by the even more hysteric efforts of Senator Joseph McCarthy.

On the labor front, the picture was mixed in the postwar years. By the end of the war, the labor movement had made major gains, having organized nearly 35 percent of the industrial work force. After the war, a strike wave swept through the nation’s industrial base. Instead of seeking to break the unions, as in earlier eras, employers worked with them to establish collective bargaining rights and improved wages and benefits in exchange for concessions to management. In 1947, a Republican-controlled Congress passed the Taft-Hartley Act, which President Truman attempted to veto. The act banned labor practices that were regarded as unfair, bolstered employers’ ability to resist unions, gave greater power to the government to intervene in disputes, and outlawed the closed shop (i.e., union-only shop), jurisdictional strikes (strikes stemming from internal union disagreements), and secondary boycotts (boycotts against firms doing business with the main target of a boycott). It also required union leaders to sign loyalty oaths stating that they were not communists. Union critics of Taft-Hartley called it a “slave labor law.” Yet, through it all, unions continued to grow and the industrial economy continued to expand.

Civil rights activity intensified but did not achieve great success in the late 1940s. President Truman desegregated the armed forces and created a presidential commission on civil rights. The Congress of Racial Equality (CORE) sponsored a “Freedom Ride” through the upper South to challenge segregation. The National Association for the Advancement of Colored People (NAACP) likewise continued its legal assault on Jim Crow laws. And the US Supreme Court issued a series of favorable rulings on civil rights. Even major league sports yielded to the trend when Jackie Robinson joined a Brooklyn Dodgers farm team in 1945 and advanced to the majors two years later. Nevertheless, at the end of the 1940s segregation was still in place in the South, and racial discrimination was still practiced in much of the rest of the country. It was not until the 1950s and 60s that the Civil Rights Movement really took off.

• Bundy, McGeorge.Danger and Survival: Choices about the Bomb in the First Fifty Years. New York: Random House, 1988.
• Byrnes, Mark S.The Truman Years, 1945-1953. New York: Longman, 2000.
• Lingeman, Richard B.The Noir Forties: The American People from Victory to Cold War. New York: Nation Books, 2012.
• May, Lary, ed.Recasting America: Culture and Politics in the Age of the Cold War. Chicago: University of Chicago Press, 1989.
• Rose, Lisle A.The Cold War Comes to Main Street: America in 1950. Lawrence, KS: University Press of Kansas, 1999.