The twentieth century's Civil Rights movement was, like the nineteenth century's Civil War, its central domestic watershed, but the parameters of the movement are less well defined than those of the Civil War. The origins of the Civil Rights movement lie in the early twentieth-century African-American struggle against the racial discrimination, disfranchisement, and segregation that prevailed in the years after Reconstruction. After 1900, African-American migration from the rural to the urban South and from the urban South to the urban North created institutions for organizing opposition to racial discrimination. In the urban South, African Americans boycotted newly segregated public transportation systems. The organization of the National Association for the Advancement of Colored People (NAACP) in 1909 and the National Urban League in 1911, with local affiliates in Northern and Southern cities, made possible longer-term campaigns for civil rights and economic opportunity. After World War I, the NAACP's...