Just like in the First World War, when America remained neutral, a similar thing happened at the beginning of the Second World War. We were forced to defend ourselves. America did not enter the war on its own but was drawn in. So the United States did not intend to be part of that global madness, but the country came to a situation where it had to defend itself. The attack on Pearl Harbor directly violated the integrity and sovereignty of the country. America was one of the world's most powerful powers at the time, so there was a moral obligation to fight the Third Reich's brutal policies and their allies.
If the United States had not been involved in the war, then the world would not be the same today. It is likely that after the Soviet Union and Britain, the United States would be the target of Hitler and his allies. Scenarios like Pearl Harbor would probably be even more so if the country had not joined the war in time. Hitler hated all those who emerged victorious from the First World War; he considered them guilty of Germany's situation. The United States was also on the list of those countries. Therefore, if America had not entered the war, and Hitler had won, the world would have been a terrible place.
