A panel of three Donald Trump-appointed judges said Friday that Mississippi was violating federal law by counting mail ballots that arrive after Election Day, but stopped short of blocking the policy before the election, in a ruling that could nevertheless impact voting-related lawsuits this fall.

The ruling from the 5th US Circuit Court of Appeals is a victory for the Republican National Committee and others who brought the case in Mississippi, a non-battleground state with very little mail-in voting, seeking a ruling by a far-right circuit court friendly to their arguments.

“Voters deserve nothing less than a fair and transparent election which ends on November 5th. We will continue to defend the law, fight for protection of every legal vote, and stop election interference in our country’s most important election,” RNC Chairman Michael Whatley said in a statement celebrating the ruling.

Democrats and voting rights advocates fear that a ruling in Republicans’ favor will be used to boost challenges to late-arriving ballots in other states, which could make the difference if the margins are tight in key races.

“Congress statutorily designated a singular ‘day for the election’ of members of Congress and the appointment of presidential electors,” the 5th Circuit panel said. “Text, precedent, and historical practice confirm this ‘day for the election’ is the day by which ballots must be both cast by voters and received by state officials.”

Among the states that allow for late-arriving ballots are Nevada, Ohio and Virginia, as does Maryland, the site of a competitive Senate race.

Also allowing for post-election ballot receipt is California and New York, both states that could make a major difference in which party controls the House of Representatives.

Even as the ruling has no immediate effect on the coming election, it could help propel any legal challenges that Republicans seek to bring against any of the roughly other 20 states and jurisdictions that count ballots arriving after Election Day. Nevada’s policies allowing the late arrival of mail ballots are already being challenged in state and federal court by Republicans, but courts in those cases so far have rejected those arguments.

Casting doubt on ballots that were not counted until after Election Day was key to former President Trump’s efforts to delegitimize and overturn the 2020 election, but Friday’s ruling was careful to specify that it’s not commenting about the actual counting of ballots after Election Day, only those received.

“That is not to say all the ballots must be counted on Election Day,” the opinion states. “Even if the ballots have not been counted, the result is fixed when all of the ballots are received and the proverbial ballot box is closed. The selections are done and final. By contrast, while election officials are still receiving ballots, the election is ongoing: The result is not yet fixed, because live ballots are still being received.”

“Although a single voter has made his final selection upon marking his ballot, the entire polity must do so for the overall election to conclude,” the court added. “So the election concludes when the final ballots are received and the electorate, not the individual selector, has chosen.”

The 5th Circuit’s ruling is only binding on the three Southern states covered by the circuit, and for now, the panel is not ordering that the policy be blocked in Mississippi for the current election, instead sending the case down for more proceedings.

Judge Andrew Oldham, joined by Judges James Ho and Kyle Duncan in Friday’s opinion, instructed the lower court to give “due consideration to ‘the value of preserving the status quo in a voting case on the eve of an election’” as it considered the next steps in the case. All three were appointed by Trump.

This story has been updated with additional details.