Vietnam War: Kent State shootings: The Ohio National Guard, sent to Kent State University after disturbances in the city of Kent the weekend before, opens fire killing four unarmed students and wounding nine others. The students were protesting the Cambodian Campaign of the United States and South Vietnam.

The Vietnam War was an armed conflict in Vietnam, Laos, and Cambodia fought between North Vietnam and South Vietnam and their allies. North Vietnam was supported by the Soviet Union and China, while South Vietnam was supported by the United States and other anti-communist nations. The conflict was the second of the Indochina wars and a proxy war of the Cold War between the Soviet Union and US. The Vietnam War was one of the postcolonial wars of national liberation, a theater in the Cold War, and a civil war, with civil warfare a defining feature from the outset. Direct US military involvement escalated from 1965 until its withdrawal in 1973. The fighting spilled into the Laotian and Cambodian Civil Wars, which ended with all three countries becoming communist in 1975.

The Kent State shootings were the killing of four and wounding of nine unarmed college students by the Ohio National Guard on the Kent State University campus. The shootings took place on May 4, 1970, during a rally opposing the expanding involvement of the Vietnam War into Cambodia by United States military forces, as well as protesting the National Guard presence on campus and the draft. Twenty-eight National Guard soldiers fired about 67 rounds over 13 seconds, killing four students and wounding nine others, one of whom sustained permanent paralysis. Students Allison Krause, 19, Jeffrey Miller, 20, and Sandra Lee Scheuer, 20, died on the scene, while William Schroeder, 19, was pronounced dead at Robinson Memorial Hospital in nearby Ravenna shortly afterward.

The Ohio National Guard comprises the Ohio Army National Guard and the Ohio Air National Guard. The commander-in-chief of the Ohio Army National Guard is the governor of the U.S. state of Ohio. If the Ohio Army National Guard is called to federal service, then the President of the United States becomes the commander-in-chief. The military commander of all forces in the State of Ohio is the Adjutant General, Brigadier General Matthew S. Woodruff is responsible for the command of 17,000 members, preparedness and readiness, installation management, and budget of the Ohio National Guard. The current Assistant Adjutant General for Army, with responsibility for overseeing the Ohio Army National Guard training and operations, is Colonel Jonathan M. Stewart. The current Assistant Adjutant General for Air is Brigadier General David B. Johnson with responsibility for overseeing the Ohio Air National Guard.