United States Declares War on Japan

Franklin_Roosevelt_signing_declaration_of_war_against_JapanThe Second World War began when Britain declared war on Germany following the latter country’s invasion of Poland in September 1939. The war in Europe quickly escalated, with the Germans next invading France, and Italy signing a pact with Hitler.

Public feeling in America was that the war was a European affair, and that it did not affect them. The U.S. government also decided that America would stay out of the war. However, there was concern about Japanese activities in Asia after that country invaded several others in the region.

Tension between the two countries had remained high since the end of World War I. After that war, Japan had been forced to disarm, and under international treaties had to keep their naval power at roughly two-thirds of that of America. This was a continuing source of resentment to the Japanese.

The Japanese unilaterally broke the disarmament treaty in 1934 and began to expand their naval power. The Japanese motivation for territorial expansion was their rising demand for energy, all of which the country had to import. To achieve their aims, they felt they needed a strong navy.





Outbreak of War

When the Japanese launched their surprise attack on Pearl Harbor, the U.S. could no longer stay at peace, and immediately declared war on Japan. Churchill followed the American declaration of war against the Japanese with a British declaration of war on that country as well.


It was almost inevitable that America would be drawn into the war in Europe once Britain had allied with them against the Japanese. Initially, the Americans were reluctant to send troops to Europe, and instead supplied much needed armaments to the British forces.

However, as the Germans invaded more and more European countries, the U.S. government and military leaders realized that they had to be stopped and began sending troops to Britain.

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