On Tuesday, the Pennsylvania Supreme Court ruled that mail-in ballots that have not been dated or are wrongly dated must be segregated from other ballots and cannot be counted.

The decision is a victory for the Republican National Committee (RNC) and other GOP-aligned groups that brought the suit in October, and it will affect thousands of votes in the state, though it is not clear at this stage how many ballots may be involved.

State officials are unsure whether there could be an appeal of the decision. Amy Gulli, a spokeswoman for acting secretary of the Commonwealth of Pennsylvania Leigh M. Chapman, said in a statement: “We are reviewing, but the order underscores the importance of the state’s consistent guidance that voters should carefully follow all instructions on their mail ballot and double-check before returning it.”

The investigative news outlet Spotlight Pennsylvania reported on Thursday that more than 1.4 million people in Pennsylvania had asked by the November 1 deadline to vote by mail.

The court’s decision is also likely to affect Democratic voters more than Republican ones as figures from the Pennsylvania Department of State analyzed by newspaper The Philadelphia Inquirer show Democrats have disproportionately made use of mail-in ballots.

When it came to those that had been returned by October 25, 79.2 percent had been returned by Democrats and just 20.8 percent by Republicans.

Those figures show that Democrats accounted for an even larger share of mail-in ballots in 2022 than 2020, when 71.2 percent of requested mail-in ballots were sought by Democrats and 28.8 percent by Republicans.

Pennsylvania Republicans accounted for just 26.8 percent of returned mail-in ballots in 2020, compared to 73.2 percent returned by Democrats.

Statistics from Pennsylvania’s Bureau of Election Security and Technology (BEST) show that 2,637,065 mail and absentee ballots were cast and counted in the 2020 election, and the turnout in the general election was 76.5 percent.

Turnout is generally lower in midterm elections, and that may be the case in 2022, despite a contentious Senate race that could determine which party controls the chamber.

Michael Berkman is director of the McCourtney Institute for Democracy at the College of the Liberal Arts at Penn State. He told Newsweek that the court’s decision is more likely to affect Democrats.

“More than three times as many Democrats - 984,000 - as Republicans - 302,000 - in Pennsylvania requested mail ballots, so any ruling that makes it less likely a ballot will be accepted will almost certainly have more impact on Democratic vote totals than on Republican vote totals,” Berkman said.

“So, yes, this ruling is a bigger problem for Democrats than for Republicans,” he said.

“In effect, a ruling like this means that someone who has followed every other step in the process outlined by the state to vote by mail, but who has mistakenly not written the date on the outside of the envelope, will be disenfranchised,” Berkman added.

“Overall, I think decisions that disenfranchise voters who have full intent of properly voting are bad for democracy, not just Democrats or John Fetterman,” he said. “We should be doing everything we can to help people vote, not to find minor errors to deny people the vote.”

Thomas Gift is founding director of University College London’s Centre on U.S. Politics, and his home state is Pennsylvania. He told Newsweek that the court’s ruling could affect the outcome of the race.

“The court’s ruling in Pennsylvania may only matter on the margins in Pennsylvania’s Senate race, but in a contest as close as Fetterman-Oz, a small difference may be all it takes to tip the scales,” Gift said.

“Conventional wisdom holds that Democrats are more likely than Republicans to vote by mail, so any technicality that could invalidate mail-in ballots is likely to favor Oz,” he said.

“If that turns out to be true, and the election ends up in ’too close to call’ territory, it will only magnify the impact of this decision,” Gift added.

Nonetheless, Gift also pointed to a 2020 study conducted by the Stanford Institute for Economic and Policy Research (SIEPR) in California that found voting by mail had “neutral partisan effects.”

“Claims that vote-by-mail fundamentally advantages one party over the other appear overblown,” the researchers said in their working paper at the time.

The Pennsylvania Senate race remains a dead heat, according to analysis from poll tracker FiveThirtyEight. The exact effect of the court’s decision on mail-in ballots may not be known for some time.

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