Which world war ii event occurred first?
the united states entered world war ii on the side of the allies.
the japanese bombed pearl harbor.

The Japanese bombed Pearl Harbor before America joined the war. America did not plan on joining the war, but was going to support their allies with resources. Japan had wanted exports from America, but the U.S. refused. Since the American government would not give to Japan, Japan decided to attack Pearl Harbor. This made the Americans furious as they had not yet enlisted and saw this as an act of terrorism. They immediately took action and joined the war.

Ibelieve it would be d hoped this !