Following the Act, black and poor white voter registration in both states increased enormously.

Mississippi also changed the process for independent candidates running in general elections.

Both these were challenged as violations of the Voting Rights Act in the respective District Courts.

In Mississippi, the District Court ordered the relevant candidates to be placed on the 1966 general election ballot, but dismissed the remaining claims completely.

In a 7—2 decision by Chief Justice Earl Warren, the Court reversed both District Courts, stating that preclearance provisions of the Voting Rights Act were applicable to all changes altering the election laws of covered states, and that no person could be deprived of the ballot for failing to comply with a new provision in a covered jurisdiction, even if they do not effect qualifications for accessing the ballot.