The Voting Rights Act of 1965, which originally was intended to prohibit barriers to black registration and voting, has been hailed as a triumph for civil rights and as a catalyst for the election of minorities to public office in both the Deep South and the urban North. To advance its objective, federal courts instructed many cities to change from at-large to single-member district electoral systems as a way to ensure that minorities had a reasonable chance to elect representatives of their choice.

In the first book to critique the implementation of this landmark legislation in a major...