A whirlwind day in the courts upended the Pennsylvania Senate Republican primary on Tuesday, when the U.S. Supreme Court stepped in to stay a critical federal ruling just hours after attorneys for both former hedge fund CEO David McCormick and celebrity doctor Mehmet Oz met in state court to fight over whether so-called “undated” ballots should be tallied in a closely divided contest.

The closely watched race between Oz and McCormick is already in a recount, which state election officials officially ordered last week. Before the recount began, Oz led McCormick by fewer than 1,000 votes. Separately on Tuesday, McCormick’s campaign said it plans on filing litigation in the state seeking to force a hand recount of ballots in a dozen counties.

The issue during Tuesday’s arguments was a narrow one: ballots where voters did not write a date on their ballots’ outer envelope. Those ballots were thrust into the spotlight for the Senate race after a federal court ruled earlier this month that similarly situated ballots should be counted for a 2021 county judicial election.