Whether the constitutional protection against racial discrimination in voting applies to a primary election used to select nominees for federal and state offices.
Holding
Yes. When state law makes a primary an integral part of the electoral process, the right to vote in that primary is protected against racial discrimination just as the right to vote in a general election is.
Reasoning
United States v. Classic established that Congress may regulate a primary when state law makes it an integral part of the machinery for choosing public officials. That recognition rejected the premise that a primary is merely an internal party affair with no constitutional significance.
Texas's primary was a practical and legal stage in the selection of officeholders. State law required major parties to use primaries for nominations and structured the general-election ballot around the nominees selected through that process. Excluding a voter from this decisive stage therefore burdened the citizen's constitutional right to participate in choosing elected officials.
The Fifteenth Amendment forbids a State from denying or abridging the right to vote on account of race. A State cannot evade that prohibition by placing the racially discriminatory barrier at the primary stage rather than at the general election.