A federal appeals court issued a ruling Monday that could gut the Voting Rights Act, saying only the federal government — not private citizens or civil rights groups — is allowed to sue under a crucial section of the landmark civil rights law.

The decision out of the 8th Circuit will almost certainly be appealed to the Supreme Court. But should it stand, it would mark a dramatic rollback of the enforcement of the law that led to increased minority representation in American politics.

The appellate court ruled that there is no “private right of action” for Section 2 of the law — which prohibits voting practices that discriminate on the basis of race.

That, in practice, would severely limit the scope of protections in the act. For decades, private parties — including civil rights groups, individual voters and political parties — have brought Section 2 challenges on everything from redistricting to voter ID requirements.