eradicated the tactics previously used in the South to disenfranchise black voters. Despite the Civil Rights Act of 1964, most Southern blacks found it difficult to exercise their voting rights. In 1965, mass demonstrations were held to protest the violence and other means used to prevent black voter registration. After a peaceful protest march at Selma, Alabama, was violently broken up by white authorities, President Lyndon B. Johnson responded with the Voting Rights Act, which abolished literacy tests and other voter restrictions and authorized federal intervention against voter discrimination. The subsequent rise in black voter registration transformed politics in the South. In 2010, Shelby County, Alabama, challenged the constitutionality of the renewal of a provision in the law requiring certain voting districts to obtain federal authorization before changing their election laws and procedures. In Shelby County v. Holder, 570 U.S. ___ (2013), the Supreme Court agreed with the county and held that the provision in the Act unconstitutionally violated the Tenth Amendment and Article Four of the U.S. Constitution.