In World War II, America's president, Franklin Delano Roosevelt, actually wanted to join the war but pretended to be neutral. The president had a document, the Atlantic Charter, that said what the world would be like when America and Britain won the war. Not to say there were no people who didn't want to join the war. The isolationist, but they were pro war after Pearl Harbour.
When America was about to join the war, we were also making an alliance with the Soviet Union. Interestingly, the Soviet Union had a non-aggression pact with Japan who were allies with the Germany. One of the main reasons that the whole world was against Germany was because of Britain uniting all of Germanys enemies. So the saying is true the enemy of my enemy is my friend.
