Pennsylvania mail ballots submitted without a date on the envelope last year should be counted, a federal appeals court said Friday, a ruling that could mean thousands more votes get counted in elections moving forward — starting with this past Tuesday’s primary.

The ruling will also almost certainly reignite the smoldering political fight over undated mail ballots; create new questions and pressure for county elections officials as they continue to count votes from this week’s primary; and create another potential opening for county-by-county legal challenges as the Senate Republican primary heads toward a likely recount.

The full extent of the decision’s impact is unclear, because the court issued a judgment and said an opinion would come later. But based on the order, lawyers from both parties said, the path was suddenly cleared for counties to count the undated mail ballots they had been preparing to reject this election.

The question before the three-judge panel in Philadelphia was whether to count 257 undated mail ballots in Lehigh County from last November’s general election. State law requires voters to sign and date the outside mailing envelope when they return their mail ballots, and state courts have held that the requirement means undated ballots must be rejected.

But throwing out those votes violates the federal Civil Rights Act, the ACLU argued, because the date isn’t actually used in determining the legitimacy of a vote. The group brought the case, Migliori v. Lehigh County Board of Elections, on behalf of five voters whose undated ballots were to be rejected after a separate case wound through state courts.

The U.S. Court of Appeals for the Third Circuit judges agreed Friday, declaring the date requirement in state law is immaterial under the Civil Rights Act — meaning it can’t be used as a reason to reject ballots.

“Accordingly, there is no basis on this record to refuse to count undated ballots that have been set aside in the November 2, 2021, election for Judge of the Common Pleas of Lehigh County,” the judgment reads. The judges returned the case to the federal district court, “and that court is hereby directed to … enter an order that the undated ballots be counted.”

The decision has implications that could extend far beyond one election in one county.

The question of whether to count undated mail ballots has been one of several fronts in the broader legal and political war in Pennsylvania over mail ballots. Republican lawmakers last year threatened to impeach Philadelphia elections officials over the issue, and the current case has drawn court filings from top Republican state lawmakers on one side and the U.S. Department of Justice on the other.

The ruling will also raise new questions for county elections officials in the process of counting votes from this week’s election and who now have to decide all over again whether to count undated mail ballots. And that comes as the Mehmet Oz and David McCormick campaigns prepare for a recount — and to fight over every vote.

Suddenly, there are more votes to potentially fight over.

The decision could have immediate impact

In recounts, the trailing candidate wants to add as many votes as possible to the count in the hopes they can change the result; the leading candidate wants to prevent any votes from getting added, protecting the lead.

An army of lawyers from across the country is descending on Pennsylvania for the Oz and McCormick campaigns, and both sides had already been discussing the possibility of Friday’s ruling, sources said.

Elections are run by counties, with the Pennsylvania Department of State, which oversees elections, providing some guidance. In every election, a number of mail ballots come in with various defects — they’re missing a signature, say, or a date — and county officials have to decide whether to accept or reject them.

The Department of State, based on rulings in state court, has told counties they should reject undated mail ballots. Many counties thought the matter had been settled, whether they liked it or not.

Now they will have to decide again: Should they count the undated mail ballots now that the federal appeals court’s order seems to give them the ability to do so? That decision will come down to the county solicitors and local elections officials.

Counties that choose to count undated mail ballots may face challenges from a campaign that wants those ballots thrown out. Meanwhile, the other side will likely try to persuade counties to add those votes into the count.

Undated mail ballots have been a flashpoint for the past two years

The question of undated mail ballots goes back to the 2020 election.

The state Supreme Court ruled that year that undated ballots be counted for that election only — but three justices interpreted state election law to allow counting undated ballots, while three justices said the law didn’t allow it. The seventh, Justice David Wecht, said undated ballots should be counted in 2020 but rejected in the future — once voters had better instructions about dating ballots and the consequences for failing to do so.

It was a complicated decision.

In the next election, Philadelphia was among the counties that moved to count undated mail ballots, after a partisan 2-1 vote, with the Democrats outvoting the lone Republican on the board.

That drew an immediate response from Republican lawmakers who control the state legislature: Follow the law as we intended it, or we will impeach you. One of the commissioners reversed course, and the ballots were rejected.

Since then, the question of undated mail ballots has continued to be a flashpoint.

And undated ballots continue to be a major cause of rejections in many counties. In Philadelphia, for example, a little more than 2,000 undated ballots were received in this primary, making it the top defect.

What the Migliori case argued — and what comes next

Last November, a Lehigh County judicial race came down to 74 votes, with Republican candidate David Ritter in the lead for a third open position over Democratic candidate Zachary Cohen.

At a hearing, the county board of elections voted unanimously to count 257 undated mail ballots, along with four ballots that had the date in the wrong location. From there, the question of the ballots has wound its way through the courts: The county court affirmed the decision to count the ballots; the Commonwealth Court overturned that, and said undated ballots should be rejected; and the state Supreme Court declined to step in.

As a matter of state law, it appeared, the issue was settled: When the law says the voters “shall” date the ballots, it meant it as a requirement that would determine whether to count or reject the ballot.

But there’s still federal law, and the ACLU of Pennsylvania quickly brought a case arguing that rejecting the ballots violated the Civil Rights Act because the date requirement isn’t used in determining whether a vote is legitimate. They lost in district court, with the judge saying the voters can’t bring the suit in the first place.

The ACLU appealed to the Third Circuit, dropping a different constitutional argument and focusing on the portion of the Civil Rights Act that says states can generally set requirements for votes but can’t use technicalities to throw out ballots.

On Friday, they won.

Lawyers for the Lehigh County elections board didn’t immediately return a request for comment Friday, so it was unclear whether they would appeal to the U.S. Supreme Court.

Staff writer Jeremy Roebuck contributed to this article.