Nations fell victim to new hostile leaders. Japan struck first, invading China. Next Italy struck at Ethiopia. Germany, under the leadership of Adolf Hitler, was the greatest fear.
Step-by-step explanation:
America was active in trade with Europe and China was assisting America's trade activities. China' interference with America is not appreciated by Japan which tried to annex china. Japan' attempt to stop china helping America is objected by Americans. The American Government stopped all the commercial vessels which headed to Japan with steel and oil. These two products were crucial for Japan to make arms and raise revenues for its country.
When the ships were frozen in the ports, Japan decided to assault the ports of America. Pearl Harbor attack resulted in death of two thousand civilians. Imperial Japan was becoming a threat which annexed China.Also Nazi Germany is also becoming a threat which made America to follow isolationism and interventionism and hence this neutral attitude made America to stay out of the war.