But a clear result could be days — if not weeks — away. Pennsylvania law requires an automatic recount if the margin of victory is within a half-percentage point. At noon Wednesday, with 96 percent of the expected ballots tabulated, Oz led McCormick by about 2,400 votes, or about two-tenths of a percentage point.
"While we look to get a better sense of the remaining votes today, we are optimistic Dr. Oz will win," his campaign manager, Casey Contes, tweeted Wednesday morning.
McCormick's team also is expressing optimism.
"Based on how many uncounted absentee ballots there are and the margin by which Dave has won them so far, that’s why we are confident of victory," Jeff Roe, McCormick's political consultant, tweeted shortly after midnight. "Dave will win this race."
The winner will face a November general election matchup against Lt. Gov. John Fetterman, who won the Democratic nomination Tuesday while hospitalized following a stroke. The race to succeed retiring Republican Sen. Pat Toomey is expected to be one of the most expensive and competitive in the country this year.
McCormick is performing better among mail-in voters than Oz is, according to real-time numbers provided by the state secretary of state's office. Under state law, counties were not able to begin counting votes submitted by mail until Tuesday morning.
In McCormick’s home base, Allegheny County, which includes Pittsburgh, 95 percent of the expected votes had been tabulated at noon Wednesday. But the remaining votes there are not likely to be counted for several days, according to elections board officials. Memory sticks from 30 precincts were mistakenly left in voting machines overnight and must be gathered before their results can be updated when the agency's Return Board convenes Friday morning, said Amie Downs, a spokesperson for the county Board of Elections. The machines are secure, Downs added.
If the unofficial statewide results remain within a half-percentage point, the secretary of state has until May 26 to order a recount, which would have to start by June 1 and conclude by June 7.
The GOP primary has been chaotic and, at times, nasty. Oz, McCormick and their allies spent a combined $25 million on advertising, with each trying to claim former President Donald Trump’s political movement. Although McCormick surrounded himself with former White House and Trump campaign advisers, Oz landed Trump’s endorsement.
Kathy Barnette, a conservative commentator whom polls showed surging late into the top tier with Oz and McCormick, seemed to acknowledge her clearer third-place finish in a video she tweeted Wednesday afternoon.
"Never forget what Sean Hannity did in this race," Barnette said, referring to the Fox News host, who endorsed Oz and provided a prime-time platform for the opposition research that surfaced against her in the closing days.
"Almost single-handedly, Sean Hannity sowed deep seeds of disinformation, flat-out lies, every night for the past five days, and that was just extremely hard to overcome, apparently. And yet over 300,000 of you came out. You refused to be tricked and bamboozled."
Trump, who continues to falsely claim that the 2020 presidential election was stolen from him, issued several messages Wednesday morning criticizing Pennsylvania's ballot-counting process.
And while Oz has urged patience as the remaining votes are tallied, Trump is advising a far more radical course.
"Dr. Oz should declare victory," Trump posted Wednesday on Truth Social, his social media website. "It makes it much harder for them to cheat with the ballots that they 'just happened to find.'"