(NewsNation) — Two days after Pennsylvania’s primary elections, celebrity Dr. Mehmet Oz and former hedge fund CEO David McCormick are still locked in a too-early-to-call race to fill the Republican nomination for a U.S. Senate seat.

As of Thursday afternoon, Oz was in the lead, with 417,023 votes — but he was only slightly ahead of McCormick, who had 415,700 votes. There were still tens of thousands of votes left to be counted, including mail ballots, as the two men vie to replace retiring two-term Republican Sen. Pat Toomey.

With Republican turnout exceeding 37% Tuesday, that makes for the highest midterm primary turnout the state has had in at least two decades.

The Hill’s Julia Manchester, noting that Pennsylvania has a closed primary, said on NewsNation’s “Morning in America” that this shows how fired up each of the party’s bases are.

“I think that these numbers are very good for Republicans if they want to be able to fire up that base, especially in a year where Democrats are facing a lot of headwinds,” Manchester said. “At the same time, though, I don’t think it paints a full picture of what’s happening with those independent and swing voters, especially those suburban voters.”

In Pennsylvania, results are all about base turnout, so it’s hard to make predictions ahead of the general election, Manchester said.

Pennsylvania’s Republican Senate election is one of the races this midterm season that will test former President Donald Trump’s sway over the Republican party. He endorsed Oz, and even encouraged him on Truth Social, the social media platform he founded last year, to declare victory in the race, according to The Hill.

Trump criticized the state’s voting procedures on social media, even though there are no indications of any wrongdoing with the ballots, other than a printing error in one county. He has criticized the state’s voting procedures since he lost in Pennsylvania two years ago — just one of many false voter fraud claims the former president has made since the 2020 election.

“I was speaking to a Republican source yesterday,” Manchester said. “They essentially said, look this is evidence that the President is worried that his brand, this brand of being undefeated in the primaries, if you will, with these elections at risk … we can guarantee you that President Trump is watching this very closely.”

Pennsylvania’s lieutenant governor, John Fetterman, won the Democratic nomination for the Senate seat hours after having surgery to implant a  pacemaker with a defibrillator to help him recover from a stroke.

Both Oz and McCormick have faced a deluge of attacks from rivals. Some conservative groups have misgivings about Oz’s position on guns, abortion and other issues, while McCormick fended off accusations he would be soft on China after leaving a hedge fund, Bridgewater Associates, which does considerable business inside the country.

Trump heavily attacked McCormick, slamming him as a liberal sellout to China who isn’t “America First.” McCormick hit back at this by airing a TV ad showing Trump telling him that he’s “served our country well in so many different ways.”

There were five primary races on Tuesday: Along with Pennsylvania, North Carolina, Oregon, Idaho and Kentucky also had races.

Several incumbent state legislators lost in North Carolina’s primary elections. On a national level, first-term U.S. Rep. Madison Cawthorn, who has long been dogged by a series of controversies, including a nude video and being cited for bringing a loaded firearm to an airport, lost his race. Now, state Sen. Chuck Edwards will face Democrat Jasmine Beach-Ferrara in the November general election.