The Pennsylvania Republican Senate primary is probably headed for a recount

It’s not over yet. And it might not be for a while.

Pennsylvania’s Republican Senate primary was still undecided Wednesday, with celebrity surgeon Mehmet Oz clinging to a narrow lead of about 2,500 votes over David McCormick. But with thousands or even tens of thousands of votes still to be counted (including both some in-person votes and mail ballots), it was unclear who would have the edge once the initial count was complete.

Either way, it appeared very likely the race would go to an automatic recount, which happens if the winning margin is less than 0.5% of the total votes cast. To avoid that, the winner would have to end up with a margin of about 6,000 to 6,800 votes. If there is a recount, it could take weeks to get a final resolution, effectively freezing the race on the Republican side.

Lt. Gov. John Fetterman coasted to a dominant victory in the Democratic Senate primary.

And even though the number of uncounted votes is likely in the tens of thousands, the voting patterns so far — showing an almost even amount of support for Oz and McCormick — suggest that neither of them is likely to suddenly run away with the race.

There were about 105,000 mail ballots that hadn’t yet been tallied into the public results as of midday Wednesday, according to the Pennsylvania Department of State, which oversees elections. Of those, it wasn’t clear how many were from registered Democrats and how many were from Republicans. Republicans have largely avoided voting by mail, with Democrats making up about three times the number of mail ballots as Republicans.

That means the number of Republican votes to be counted in the race is much smaller.

» READ MORE: 5 takeaways from the Pennsylvania primary election

It’s impossible to know exactly how many Republican votes remain to be counted, in part because some, such as overseas and military ballots, are still coming in.

A much bigger but still unknown number of uncounted ballots are the in-person votes from voting machines that haven’t yet been uploaded to the state’s election system. That happens every election, often because of human error — a poll worker accidentally taking home a voting machine USB drive, say, or returning the voting machine results cartridge to the wrong place.

As counties chase down those final voting machine numbers, the tally of fully counted precincts will rise, and the vote counts will tick upward.

There are also always a number of mail ballots that counties will have to adjudicate because there’s some sort of question about them. For example, if a voter returned a ballot to a drop box in another county, should it still be counted? And there are also an unknown number of provisional ballots, only some of which will be counted.

That all adds up, as of Wednesday, to likely tens of thousands of votes.

The below graphic shows the most recent results reported. It is updated in real time.

Pennsylvania law calls for the secretary of state, who oversees elections, to order a recount by 5 p.m. the second Thursday after the election. That would be Thursday of next week, or May 26.

Leigh Chapman, Pennsylvania’s acting secretary of state, said Wednesday on CNN that she’d have a good sense by Tuesday of whether the state would automatically recount votes in the race. If there is a recount, Chapman would issue an advisory next Wednesday, then officially order the recount Thursday.

”Unofficial returns come to me on Tuesday, so I’ll have a very good sense,” Chapman said.

Both candidates acknowledged the uncertainty in addressing supporters late Tuesday night.

“Right now, we have tens of thousands of mail-in ballots that have not been counted that are gonna need to be counted beginning tomorrow,” McCormick told several dozen friends and family at an election night party in Pittsburgh. “So unfortunately we’re not going to have a resolution tonight, but we can see the path ahead. We can see victory ahead.”

“We’re not going to have a result tonight,” Oz told his supporters at the Newtown Athletic Club in Bucks County. “When all of the votes are tallied, I am confident we will win.”

» READ MORE: What to know about Pennsylvania’s election recount rules

There were several other tight, critical contests still up in the air Wednesday.

In the Pittsburgh-based 12th Congressional District, only about 440 votes separated State Rep. Summer Lee from her Democratic primary rival Steve Irwin. The winner of that race will almost certainly be headed to Congress given the district’s deep-blue politics.

Meanwhile, the Republican primaries in two competitive congressional districts were also too early to call. In the 6th District, based in Chester County, Guy Ciarriocchi led by about 2,000 votes over Steve Fanelli in a contest that will decide who faces Democratic Rep. Chrissy Houlahan in the general election.

And in the 7th District, in the Lehigh Valley, Lisa Scheller was leading Kevin Dellicker by a little less than 2,000 votes in the Republican primary. The winner will run against Democratic Rep. Susan Wild. Scheller was the GOP nominee in 2020.

Both parties have made the 6th and 7th Districts top priorities as Republicans aim to take control of the House.

Staff writers Anna Orso, Julia Terruso, and Sean Collins Walsh contributed to this article.