King's victory in Montgomery prompted him to launch an attack on Jim Crow that eventually encompassed the entire South. He became the recognized leader of the civil rights movement that rid the United States of racial segregation sanctioned by law. His movement also enabled black citizens in the South to exercise their right to register and vote. The civil rights movement changed the political and social face of the nation.

Even during King's civil rights movement, however, black leaders often clashed over both goals and tactics. Malcolm X and his Black Muslims challenged King's integrationist message, calling for a separate black nation and economic system. The Black Panther Party, established during the mid-1960s, rejected King's call for nonviolent protest; Black Panthers armed themselves and fought several bloody battles with law enforcement officials. These civil rights activists of the...