Four Kent State University students were killed and nine were injured on May 4, 1970, when members of the Ohio National Guard opened fire on a crowd gathered to protest the Vietnam War. The tragedy was a watershed moment for a nation divided by the conflict in Southeast Asia. In its immediate aftermath, a student-led strike forced the temporary closure of colleges and universities nationwide. Some political observers believe the events of that day in northeast Ohio tilted public opinion against the war and may have contributed to the downfall of President Richard Nixon.
https://www.history.com/topics/vietnam-war/kent-state-shooting
https://www.history.com/topics/vietnam-war/kent-state-shooting