What caused the US to go into WWII?

Answer 1

The United States entered World War II primarily due to the Japanese attack on Pearl Harbor on December 7, 1941, which killed over 2,400 Americans and galvanized public opinion in favor of entering the war. Prior to this, the U.S. had been providing support to Allied nations through programs like Lend-Lease, but isolationist sentiment was strong. The attack shifted the U.S. from a stance of neutrality to active involvement in the conflict against the Axis powers. Subsequently, on December 8, 1941, President Franklin D. Roosevelt declared war on Japan, marking the official entry of the U.S. into World War II.