What significant event occurred on December 7, 1941, prompting the United States to enter World War II?

The attack on Pearl Harbor on December 7, 1941, was a pivotal moment in World War II that led to the United States' entry into the conflict. This surprise military strike by the Imperial Japanese Navy aimed to eliminate the U.S. Pacific Fleet and prevent American interference in Japan's expansion efforts in Southeast Asia. The attack resulted in significant loss of life and damage to naval vessels and aircraft, galvanizing public opinion in the United States and leading to a swift declaration of war against Japan.

This event marked a turning point not only for the U.S. but also in the broader context of the war, as it shifted the landscape of global alliances and military strategies. Prior to Pearl Harbor, the U.S. had maintained a policy of neutrality, although it had been providing support to Allied powers through programs like Lend-Lease. The attack fundamentally changed the United States' role in the war, transitioning it from a neutral country to an active combatant in both the Pacific and European theaters.