After the U.S. Supreme Court ruled racial segregation in public schools to be unconstitutional in "Brown v. Board of Education" in 1954, Oak Ridge High School in 1955 became the first school in Tennessee to be integrated. The next year, nearby Clinton High School was integrated, and Tennessee National Guard troops were sent in after pro-segregationists threatened violence. Between February and May 1960, a series of sit-ins at segregated lunch counters in Nashville organized by the Nashville Student Movement resulted in the desegregation of facilities in the city. On April 4, 1968, James Earl Ray assassinated civil rights leader Martin Luther King Jr. in Memphis. King had traveled there to support striking African American sanitation workers.