World War II and the attack on Pearl Harbor led the U.S. to realize the importance of international participation.
The event that convinced the U.S. of the need for participation in an international organization was World War II.
This was primarily triggered by the Japanese attack on Pearl Harbor on December 7, 1941, which prompted the U.S. to enter the war.
This event unified the nation against common enemies and marked a significant period of growth and maturity in American culture.
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