In the Spanish-American War it was the sinking of the Maine that provided the punishment justification for war. In World War I it was the sinking of the Lusitania, in World War II it was Pearl Harbor, in Korea it was an unprovoked attack on American troops, in Vietnam it was the Gulf of Tonkin Incident, and in the Gulf War it was the invasion of Kuwait, and in Afghanistan and Iraq it was 9-11 and the possibility of weapons of mass destruction.[3]
