League of Nations
An international organization was formed to allow nations to discuss problems and prevent war; the U.S. did not join.
A worldwide depression started in the decade after the end of the war.
Losing nations were forced to disarm; they resented it and defied the order.
After the war and during the Depression strong leaders(for example, Adolph Hitler) gained power in many nations.
Rebellion in the colonies
Colonists wanted freedom.