The Civil Rights Movement brought renewed attention to black voting rights. Florida voting rights activists Harriette Moore and Harry T. Moore were assassinated by the KKK in 1951. In "Gomillion v. Lightfoot" (1960) the Supreme Court struck down a plan to redraw the district lines of Tuskegee, Alabama, on the grounds that it would disenfranchise black voters. The Twenty-fourth Amendment to the United States Constitution, passed in 1962–1964, banned poll taxes as a precondition for voting in federal elections. The Supreme Court ruled against state poll taxes in 1966 in "Harper v. Virginia State Board of Elections". Civil rights leaders began organized campaigns to register black voters, including the federally endorsed Voter Education Project. A particularly intense voting rights struggle in Mississippi led to the death of Medgar Evers in 1963 and of three civil rights volunteers during the Freedom Summer campaign in 1964. Organizers also created the Mississippi Freedom Democratic Party to challenge the white-dominated Mississippi Democratic Party. In Alabama, the highly publicized Selma to Montgomery marches in 1965 met with a violent response, bringing more scrutiny to suppression of black voters. The Voting Rights Act of 1965 prohibited a variety of discriminatory state voting practices. The Supreme Court upheld this law in the 1966 decision "South Carolina v. Katzenbach".