Martin Luther King Jr. (1968)

The assassination of Martin Luther King Jr. on 4 April 1968 remains the most consequential modern political murder in American history, outpacing #6 Gandhi in immediate domestic upheaval. James Earl Ray's single shot in Memphis — fired the night before King was to lead a march supporting striking sanitation workers — ignited riots across over 100 U.S. cities, causing an estimated $50 million in property damage. King's death permanently crippled the civil rights movement's nonviolent wing, accelerating a shift toward more confrontational politics that his leadership had uniquely contained.