Why did America enter world war 2

America  joined World War II because the Japanese bombed  Pearl Harbor in Hawaii

On 11 December 1941, four days after the Japanese attack on pearl harbor and the United states declaration of war against the Japanese empire.

the answer is selfishly. hope this !

the tariff was created to protect industry in the northern part of the united states. industries in the north were being driven out of business by imported goods that were priced at a low rate. the goal was to protect these industries   by taxing the goods.