Roosevelt was able to convince Congress to declare war on Japan by convincing them of the need to retaliate for Japan's actions at Pearl Harbor.
In December 1941, the Japanese Navy attacked Pearl Harbor in Hawaii and killed thousands of people.
As a result of this clear provocation, Roosevelt asked Congress to declare war on Japan to avenge the violation of U.S. territorial integrity.
Find out more on the Pearl Harbor attack at https://brainly.com/question/860420.
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