Trump support of Dr. Oz puts kingmaker status to the test in 3-way Pennsylvania GOP primary race

President Donald Trump's status as kingmaker of the GOP is being put to the test in a three-way GOP primary race Tuesday in the battleground state of Pennsylvania.

Celebrity talk show host Dr. Mehmet Oz is running against veteran and adjunct professor Kathy Barnette and David McCormick, veteran and former Treasury Department official in the George W. Bush administration.

Trump threw his support behind Oz over the other leading candidates on April 25. Since then, some conservatives, such as former Trump appointee Jack Brewer, have said Trump got his endorsement wrong, arguing that Oz "does not represent American Christian principles that this nation was founded on."

Barnette has been surging in the polls of late, prompting Trump to release a statement explaining why he's backing Oz over Barnette.

"Kathy Barnette will never be able to win the General Election against the Radical Left Democrats," Trump said in a statement. "She has many things in her past which have not been properly explained or vetted, but if she is able to do so, she will have a wonderful future in the Republican Party — and I will be behind her all the way."

Trump said Oz is "the only one who will be able to easily defeat the Crazed, Lunatic Democrat in Pennsylvania."

Barnette made headlines on Monday after pictures of her at the Jan. 6 rally that preceded the Capitol riot surfaced. Her campaign clarified why she attended.

"Kathy was in DC to support President Trump and demand election accountability," a Barnette campaign spokesperson said in a statement. "Any assertion that she participated in or supported the destruction of property is intentionally false. She has no connection whatsoever to the proud boys. There is no doubt that 2020 had unprecedented irregularities. America deserves transparency to restore faith in our system."

Oz was asked about election integrity on Monday, a topic he hasn't elaborated on much during the course of the campaign.

"There's so many questions," Oz said when addressing the 2020 election results, adding that voter ID is a "critical" issue in elections.

David Brody, host of the "Water Cooler" television show, noted that Oz has not used words like "rigged or stolen" like former President Donald Trump uses to describe the 2020 election.

"I want to be careful," Oz said. "Republicans are about fixing things. I know for sure we've got to deal with 2020, but this is about knowing exactly what the diagnosis is so we can give it the right treatment."

The state's Lt. Gov. John Fetterman, former mayor of Braddock, is the frontrunner in the Democratic Senate primary. Fetterman suffered a stroke just ahead of Election Day, but he's reportedly recovering well. Fetterman is running against Rep. Conor Lamb (D-Pa.).

Trump was the first Republican presidential nominee to win the state of Pennsylvania in the general election since former President George H. W. Bush in 1988. Trump lost the swing state in 2020 against President Joe Biden.

Despite Barnette's rise in the polls, Oz and McCormick remain in the lead, with Oz pulling ahead slightly, according to recent polling.

Conservatives such as Texas Republican Sen. Ted Cruz have hit the campaign trail for McCormick in the final days of the race.

The polls open in Pennsylvania at 7 a.m. on Tuesday and close at 8 p.m.