What is one reason the United States entered World War II?

The United States entered World War II primarily as a response to the attack on Pearl Harbor on December 7, 1941. This surprise military strike by the Japanese Navy against the U.S. naval base at Pearl Harbor, Hawaii, resulted in significant losses, including the sinking of battleships and the loss of many lives. As a direct consequence, this attack galvanized public opinion in the United States and united the nation in support of entering the war.

The significance of this event cannot be overstated, as it shifted the U.S. from a position of isolationism to active involvement in the conflict, declaring war on Japan the following day. This response was crucial, as it marked a turning point in the war, leading to the U.S. joining the Allied Powers and ultimately contributing to the defeat of Axis powers.

In contrast, while other events such as the invasion of Poland and the sinking of the Lusitania did impact U.S. foreign policy, they occurred in different contexts and did not catalyze a direct U.S. military response at the time. The bombing of Tokyo is also less relevant in the context of the reasons for entering the war, as it occurred after the U.S. had already engaged in the conflict.