The process of drawing US electoral district boundaries due to population changes reflected by the census, known as redistricting, is regulated by federal law. Districts with a history of voting discrimination against racial-ethnic minorities, like many in the South, must meet requirements of the Voting Rights Act 1965). Section 5 requires that districts pre-clear any change in suffrage laws with the Department of Justice.

Early compliance was slow. Some southern states diluted black votes by instituting at-large elections and multimember districts, changing elective into appointive positions, and restricting minority candidates’ ability to appear on the official ballot. But the Supreme Court rejected such measures in Allen v. State Board of Elections (1969) for Virginia and Mississippi, and in White v. Register (1973) for Texas. Black and Latino voters, it stated, must have “equal opportunity to participate in the legal processes and to elect legislators of their choice.” This anticipated majority–minority Congressional Districts in the 1990s.