What caused the u. s. to enter world war il?

The US never wanted to join World War II so they isolated themselves from everything that was going on and tried to stay neutral (Over time, we sided with the Allies). Mainly, we entered due to the Japanese attack on Pearl Harbor. After the bombing, the US decided to declare war on Japan. Soon after, Nazi Germany's leader declared war on the US and then the US was officially in the war.

So, all in all, it was the bombing of Pearl Harbor on December 7, 1941.

Hope this helps :)

Because of the bombing of pearl harbor

our former president bush did 9/11

chamberlains goal was to stop the uk ad germany from fighting which he went to hitler and asked if he could sign a peace treaty between germany and the uk