The Impact of U.S. Participation in WW2

by Hunkar Ozyasar; Updated September 26, 2017

The Second World War was the biggest military conflict in history and shaped the future of not only the fighting nations, but also the rest of the world. While the United States was at first reluctant to enter the war, the Japanese attack on the American base in Pearl Harbor on December 7, 1941 pushed the nation into the conflict.

Power Balance

The entry of the United States into the war shifted the balance of power. While the German army had a dominant position on practically all fronts between the start of the war in September 1939 and the end of 1941, the huge American military machine tilted the balance in favor of the allied nations of France and Britain. At first, the U.S. focused on ramping up the production of military supplies at home. In fact, almost a year passed until American forces directly confronted the German military. Particularly in 1943 and 1944, however, the presence of American forces proved critical and is perhaps the single most important factor determining the outcome of the war.


American participation in the war meant that the technological know-how of the nation could be put to use. The Germans had highly advanced technology, and the development of new weapons systems was an absolute must to cope with the might of the axis forces, made up of Italy, Japan and Germany. Perhaps the biggest innovation was the development of the atomic bomb. American and British scientists, working in secret, developed and tested atomic bombs on American soil. Two such bombs were used against the Japanese, accelerating the end of the war. This technological advancement later led to the creation of atomic reactors. In 1953 President Eisenhower's "Atoms for Peace" program was rolled out. This initiative helped the United States apply the knowledge gained during the war for the development of civilian energy. The first reactor started manufacturing electricity in Pennsylvania in 1957 and operated until 1982.

Domestic Economic Impact

The entry of America into the war necessitated a tremendous increase in the output of military supplies. As a result, the number of unemployed Americans decreased from over 8 million before the start of the war to nearly zero by 1941. Many factories that were producing civilian machinery were converted into military suppliers. Although female representation in manufacturing was very low before the war, many women started working in factories. Rosie the Riveter, a female character representing female factory workers became a popular American icon. Both men and women developed critical skills, which helped employers find suitable workers with ease after the end of the world war.

The Aftermath

At the end of the war, the United States, as one of the chief architects of victory, played a major role in the development of Europe. The Marshall Plan, which was an economic development program for European nations, helped rebuild Europe. The close involvement of America in the rebuilding of the continent also allowed American values of democracy and freedom to spread throughout most of Central Europe. Had America not entered the war, such close involvement in the rebuilding efforts would not have been possible. Unfortunately, the close alliance between America and most Central European nations pushed Russia to build its own support system in the form of the Eastern Bloc, and the subsequent Cold War lasted 40 years.

About the Author

Hunkar Ozyasar is the former high-yield bond strategist for Deutsche Bank. He has been quoted in publications including "Financial Times" and the "Wall Street Journal." His book, "When Time Management Fails," is published in 12 countries while Ozyasar’s finance articles are featured on Nikkei, Japan’s premier financial news service. He holds a Master of Business Administration from Kellogg Graduate School.

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