CNN  — 

The Republican primary for Pennsylvania’s US Senate race, which could be key to determining control of the chamber in November, was too close to call early Wednesday as Mehmet Oz and Dave McCormick battled for the top spot with thousands of mail-in ballots still to be counted.

The race to replace retiring GOP Sen. Pat Toomey had been dominated by millions of dollars in negative advertising, mostly between Oz, the celebrity doctor backed by former President Donald Trump, and McCormick, a former hedge fund executive, and their allies.

In the final days before Tuesday’s primary, political commentator Kathy Barnette had appeared poised for a late surge as she tried to claim the “Make America Great Again” label, attempting to channel concerns about Oz’s conservative bona fides among Trump supporters. But by early Wednesday, Barnette was trailing in third place.

While Oz held a razor-thin lead Wednesday morning, advisers to McCormick were confident of their candidate’s path to victory.

“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. Dave will win this race,” Jeff Roe, chief strategist to the McCormick campaign, wrote in an overnight message on Twitter.

An adviser to Oz pointed to ballots yet to be counted in Philadelphia, where the candidate currently holds a double-digit edge, as well as several counties across the eastern edge of the commonwealth where he is leading McCormick.

“It’s a jump ball,” the Oz adviser told CNN.

Pennsylvania Lt. Gov. John Fetterman, who suffered a stroke last week that kept him in the hospital for the final days of the primary, will win the Democratic nod for Senate, CNN projected Tuesday. His victory over moderate Rep. Conor Lamb is a win for progressive Democrats in a race that represents the party’s best chance of flipping a seat this fall.

It appeared to be a mixed night for the former President, who has been preoccupied with trying to pick winners in midterm contests ahead of a possible 2024 White House bid. One of the candidates he backed in an 11th-hour endorsement – Pennsylvania Republican Doug Mastriano, who championed his election lies – will win the gubernatorial nod in the Keystone State, CNN projected.

But one of Trump’s acolytes in Congress, North Carolina Rep. Madison Cawthorn, was ousted after a fierce campaign to unseat him by some of his fellow Tar Heel Republicans – proving that Trump isn’t enough of a lifeline to rescue the most controversial candidates.

In Idaho, incumbent GOP Gov. Brad Little will win reelection, CNN projected, fending off an unusual challenge from his lieutenant governor, Janice McGeachin, whom Trump had endorsed.

Election denier wins Pennsylvania gubernatorial primary

In a state that was pivotal to the 2020 election, Mastriano is seeking an office that would allow him sway over the state’s electors in the 2024 presidential contest. He will face Democrat Josh Shapiro, the current state attorney general, in November.

In a taste of the bruising race to come, Shapiro immediately put out a statement Tuesday night calling Mastriano “a dangerous extremist who wants to take away our freedoms,” charging that the Republican would seek to “restrict the vote and spread conspiracy theories.”

Mastriano took a leading role in amplifying those false claims, and spent more than $3,000 from his campaign account to charter buses to Washington ahead of the January 6, 2021, “Stop the Steal” rally that preceded the attack on the US Capitol, according to state campaign finance records.

In the immediate aftermath of the insurrection, Mastriano condemned the violence in a video posted on Facebook, but video and pictures from the event show him near the Capitol, raising questions about his involvement.

In his victory speech Tuesday night, Mastriano rejected the “extreme” label, arguing that Democrats’ Covid-19 public health measures were extreme.

“On day one, any mandates are gone. On day one, any jab for job requirements are gone,” he said to cheers. “There is a movement here that is going to shock the state this November.”

Madison Cawthorn loses

Cawthorn, the controversial freshman congressman backed by Trump, conceded his North Carolina primary to state Sen. Chuck Edwards on Tuesday evening, according to Cawthorn’s spokesperson.

Cawthorn’s concession marked a stunningly quick fall for a young conservative once viewed as a potential star within the GOP after he succeeded Mark Meadows, who left Congress to become chief of staff to Trump.

North Carolina Sen. Thom Tillis had backed Edwards, telling CNN it was the first time in his career that he’d opposed a sitting Republican.

Edwards confirmed the concession call in remarks to supporters Tuesday night.

“I received a call from Congressman Cawthorn just a few minutes ago. Just as I expected, he presented himself in a very classy and humble way and offered his support to our campaign in absolutely anyway that we can use him.”

In North Carolina’s Senate race, Rep. Ted Budd will win the GOP nomination to replace retiring North Carolina Sen. Richard Burr, CNN projected Tuesday.

Trump endorsed Budd nearly a year ago, but his candidacy was slow to take off and he struggled to break away from former Gov. Pat McCrory and Rep. Mark Walker in the primary. Heavy spending from the Club for Growth’s political action committee ultimately boosted the conservative congressman, who backed voting to toss out the electoral results in Arizona and Pennsylvania in January 2021.

Democrat Cheri Beasley, who was the first Black woman to lead the North Carolina Supreme Court as chief justice, will be the party’s Senate nominee in the state, CNN projected Tuesday. Her main rivals had dropped out of the primary before Tuesday.

A test for Biden too

Farther west, Democrats are closely watching a House primary in Oregon’s newly drawn 5th Congressional District, where Rep. Kurt Schrader is fending off a challenge from his left from Jamie McLeod-Skinner, who has received a relatively modest boost from progressive outside groups, led by the Working Families Party.

Schrader, who was President Joe Biden’s first congressional endorsement of 2022, has angered some of his fellow Democrats by voting against the American Rescue Plan, Biden’s $1.9 trillion Covid relief package, and a measure in the President’s Build Back Better package to allow the government to negotiate the price of pharmaceutical drugs, which would dramatically lower prices.

Schrader pushed an alternative provision and ultimately voted for the full bill, but not before joining a group of nine moderates in an effort to decouple it from the bipartisan infrastructure bill – a tactical step that ultimately helped doom Build Back Better, Biden’s would-be signature legislation – in the Senate.

CORRECTION: A previous version of this story mischaracterized the potential historic significance of Barnette winning the Pennsylvania Senate seat. She would become the first Black Republican woman elected to the Senate.

CNN’s Greg Krieg and Jeff Zeleny contributed to this story.