The U.S. Supreme Court on Monday sent back a closely watched Voting Rights Act dispute brought by two Native American tribes, directing lower courts to reconsider a ruling that had narrowed a key way voters and advocacy groups can enforce the 1965 law. The justices said the lower-court decision needed review after the Supreme Court’s own earlier ruling weakened aspects of Voting Rights Act enforcement.

In the North Dakota case, the 8th U.S. Circuit Court of Appeals had held that only the federal government could sue to enforce the Voting Rights Act. The Supreme Court’s order instead directed the lower courts to revisit that approach, which the higher court said undercut an enforcement mechanism central to many Section 2 lawsuits—those brought by voters and advocacy groups rather than the federal government alone.

According to the Supreme Court’s order, the stakes extend beyond the North Dakota case. The ruling jeopardized similar arguments in other litigation over election maps, including an appeal involving Mississippi’s legislative map that the high court also sent back for reconsideration on Monday.

Lenny Powell, an attorney with the Native American Rights Fund, said in response to Monday’s action that the Supreme Court’s decision to toss out the appeals court’s ruling was the right call. He said he would “keep fighting to ensure that Native voters have the ability to vote and effect change in their communities.”

The Supreme Court’s order builds on its April decision that limited how plaintiffs can win some Voting Rights Act challenges. In that April ruling, the conservative majority struck down a majority Black congressional district in Louisiana and made future map cases harder to win by setting a demanding standard for how race may be used in districting.

In Monday’s orders, Justice Ketanji Brown Jackson dissented from both decisions. She said she would have left in place the Mississippi ruling and fully reversed the decision in the North Dakota case.

The practical impact of Monday’s Mississippi and North Dakota developments may take time. Damon Hewitt, president and executive director of the Lawyers’ Committee for Civil Rights Under Law, said the changes could affect three new majority-Black state legislative districts, but that any effects likely would not be felt until 2027.