The Supreme Court on Friday rejected an emergency appeal from Republicans that could have led to thousands of provisional ballots not being counted in Pennsylvania as the presidential campaigns vie in the final days before the election in the nation’s biggest battleground state.

The justices left in place a state Supreme Court ruling that elections officials must count provisional ballots cast by voters whose mail-in ballots were rejected.

The ruling is a victory for voting-rights advocates, who had sought to force counties — primarily Republican-controlled counties — to let voters cast a provisional ballot on Election Day if their mail-in ballot was to be rejected for a garden-variety error.

While the Supreme Court action was a setback for Republicans, the GOP separately claimed victory in a decision by Pennsylvania’s Supreme Court. That court rejected a last-ditch effort by voting rights advocates to ensure that mail-in ballots that lack an accurate, handwritten date on the exterior envelope will still count in this year’s presidential election.

The rulings are the latest in four years of litigation over voting by mail in Pennsylvania, where every vote truly counts in presidential races. Republicans have sought in dozens of court cases to push the strictest possible interpretation for throwing out mail-in ballots, which are predominantly cast by Democrats.

Taken together, Friday’s near-simultaneous rulings will ensure a heavy emphasis on helping thousands of people vote provisionally on Election Day if their mail-in ballot was rejected — and potentially more litigation.

As of Thursday, about 9,000 ballots out of more than 1.6 million returned have arrived at elections offices around Pennsylvania lacking a secrecy envelope, a signature or a handwritten date, according to state records.

Pennsylvania is the biggest presidential election battleground this year, with 19 electoral votes, and is expected to play an outsized role in deciding the election between Republican Donald Trump and Democrat Kamala Harris.

It was decided by tens of thousands of votes in 2016 when Trump won it and again in 2020 when Democrat Joe Biden won it.

A voting-rights lawyer in Pennsylvania who helped bring both cases said it is almost certain that another case over undated ballots will be back before the state Supreme Court within days after the presidential election if it is close.

“It’s almost certain that this is going to be raised again after the election, especially if it’s a close election,” Witold Walczak, legal director of the American Civil Liberties Union of Pennsylvania, said in an interview.

In its unsigned, two-page order, the state’s highest court put a lower court ruling on hold that would have required counties to count the ballots. The high court said the case won’t apply to the presidential election being decided next week, but held out the possibility that it would still rule on the case at a later time.

The rulings came as voters had their last chance Friday to apply for a mail-in ballot in a bellwether suburban Philadelphia county while a county clear across the state gave voters who didn’t receive their ballot in the mail another chance to get one. A judge in Erie County, in Pennsylvania’s northwestern corner, ruled Friday in a lawsuit brought by the Democratic Party that about 15,000 people who applied for a mail ballot but didn’t receive it may go to the county elections office and get a replacement through Monday.