The Supreme Court’s decision, by a 7-to-2 vote — Justices Sonia Sotomayor and Ketanji Brown Jackson dissented — to overturn the United States Court of Appeals for the Third Circuit’s decision that  mail-in votes do not require a date to be counted could upend a pivotal Senate race and signal a new era in voting jurisprudence.

The facts of the case — Ritter v. Migilori — are fairly modest. It turns on just 257 undated mail ballots from an already decided judicial contest in Pennsylvania’s Lehigh County. The underlying issue, however — whether to count undated ballots — could have a decisive impact on next month’s midterm elections. 

The decision to intervene stands in marked contrast to the hands-off approach adopted during the 2020 election, when the Supreme Court left the protocols of administering and counting the vote to state legislatures and courts despite pleas for intervention from President Trump. 

Pennsylvania state law seemed to suggest that ballots required dates, an expectation ratified in a series of state court holdings. That expectation was upended when the riders of the Third Circuit ruled that because any date was acceptable, the entire requirement was superfluous. 

That superfluity in turn led the Third Circuit to hold that the law violated federal law, specifically the materiality provision of the Voting Rights Act. That clause holds that simple “errors or omissions” do not capsize an otherwise valid ballot. Democratic challengers to the law labeled it a “meaningless technicality.”

While the decision will not undo the results of that judicial election, it means that the Third Circuit’s ruling cannot be used as precedent in those jurisdictions under its sway, which include  Pennsylvania, New Jersey, and Delaware.

By vacating the Third Circuit’s holding, the Supreme Court has opened the field for a fresh round of litigation. The issue has already been litigated in one tight race; the Republican primary for Senate, when David McCormick successfully argued for dateless ballots to be counted. It was a Pyrrhic victory, as he lost the election to Mehmet Oz. 

The high court’s ruling comes down in the midst of another tight race, this time between John Fetterman and Dr. Oz for the Senate seat opened up by the retirement of Senator Toomey. Republicans convinced the court that the Third Circuit ruling threatened to “invalidate countless regulations of mail-in voting.”

The justices are not unfamiliar with election challenges emanating from Pennsylvania. In the 2020 election, they declined to hear Mr. Trump’s challenge to a state supreme court decision requiring election officials to receive and count mailed-in ballots that arrived up to three days after the election.

Justice Clarence Thomas dissented from that decision to decline the matter, labeling the abstention “befuddling” and “inexplicable” given that the suit provided an “ideal opportunity” to weigh in on the role of state courts in deciding on election procedure.