The involvement of the United States in World War I was inevitable. If the U.S. had not entered the war, the result may have swung the other way. However, with their involvement in the war, the Allies were able to seal their final victory through military aid from the United States in the form of troops, rations, supplies, and war vehicles. The United States' involvement in World War II was also inevitable, mainly because of the attacks made on American ships by the Germans, and the attack on Pearl Harbor. If no retaliation had taken place, it would have made America seem weak and afraid of Germany and Japan. The involvement in the war was overdue in the sense that FDR had previously stated that the United States would be one of the main powers to defend democracy and would defend any country subject to control by oppressive powers.
America's view point of entering World War I leaned mostly to a neutral stand point.
Although many Americans felt like they had a brotherly tie to Great Britain and favored the Allies obtaining victory, most found no reason for entering the war. This was mainly due to the fact that there had been no direct attack made on the United States, and the war was on the other side of the globe. During World War II Americans once again remained neutral. There were many campaigns to promote isolationism and antiwar spirits such as a campaign to get rid of Memorial Day because decorating soldiers' graves glorified wars.
The German response declaring that they would sink any Allies' ships on sight and the Zimmermann note were the first two events that led to America joining the war. The Zimmermann note suggested an alliance between Mexico and Germany and promised that Germany would...