Secane, Pennsylvania (CNN) Celebrity TV host Mehmet Oz arrived at a fire station in a small town outside Philadelphia on Saturday, seeking to convince the roughly 25 people gathered that he was a real part of the MAGA movement created by the man who backed him, former President Donald Trump.
The challenges have stacked up against Oz in the crucial Pennsylvania Senate Republican primary, from one opponent's relentless attacks portraying him as a "Hollywood liberal" to a late surge by another candidate embraced by the grassroots.
But here in Secane, Oz portrayed himself as the kind of conservative who would "never let you down," proudly noting Trump said he is the most electable GOP candidate in the race that could determine the future party control of the Senate.
"One of the reasons that President Trump endorsed me," the heart surgeon told the potential voters gathered here, "was because after doing all the work of calculating who's most likely to win in November he decided I was the person."
Afterward, Oz appeared to win over at least one undecided voter, who had seen the attacks critiquing Oz's past, more moderate views on abortion and gun control. Jonathan Menta, a 52-year-old corporate audit manager, said he was impressed by Oz's pitch, especially on increasing natural gas production in the state, and could now see himself supporting him.
"I received a lot of literature at my home that say that Dr. Oz is more Republican in Name Only," Menta said. "It sounds like today though, if he's true to his word and what he was speaking about today, that those may be mischaracterizations of his positions."
Richard Koehler didn't need to be convinced: He was already all in for Oz. "I like his ideas, his questions. He's a conservative by nature and seems genuine."
The fact that Trump endorsed Oz, "put the icing on the cake."
Tuesday's primary will not only nominate a GOP candidate in the pivotal Senate race but will also be the latest test of Trump's sway over the Republican Party.
Dozens of Trump supporters at rallies this past week for deep-pocketed candidate David McCormick said that Trump's endorsement did not factor into their decision, and expressed a distrust and dislike of Oz.
Jeff McHugh, 46, described Oz as a RINO -- "Republican In Name Only" -- and said he thought Oz was only running as a Republican because he had determined he could win the most support among that group of voters.
"I'm definitely a pro-Trump guy, but that doesn't mean I'm pro-Oz," McHugh said.
Larry, a 66-year-old retired contractor wearing a MAGA hat, described Oz as "phony" and "fake."
"He's going to be a turncoat. I don't trust him. He's got that look about his face. He's got that smirky smirk that I don't like," Larry said. He said he "can't imagine" why Trump endorsed him.
Pennsylvania Republican Sen. Pat Toomey, whose retirement created the race for the open seat, told CNN "it's hard to say" how much of a difference Trump's endorsement of Oz is going to make.
"I think it's quite possible that it won't be a huge factor," said Toomey, because Oz is already so well-known after 13 seasons of his daytime TV talk show. Toomey has not endorsed a candidate.
Interviews with dozens of Republican voters across the state reveal many are waiting until the last moment to decide which candidate they'll cast their ballot.
Rich Walzak, 64, said he's still undecided because he's looking for a candidate who is trustworthy, committed to following through on promises and can beat a Democrat in November.
"Everybody has good points, but I'm looking for somebody, whether it's a man or a woman -- just keep your word. Be true to yourself," Walzak said. "But you have to be realistic. It's not so much who you like, it's who can carry the bag."
The latest Fox News public poll shows Oz is statistically tied with hedge fund McCormick and political commentator Kathy Barnette. Barnette, a Black woman, has surged at the last minute, even though her campaign is spending just $63,000 on air in the final week of the race.
She grew her support from within the MAGA movement, after refusing to concede her 19-point loss for a US House seat in 2020, organizing buses to attend Trump's "Stop the Steal" rally on January 6, 2021, and searching for fraudulent votes. She campaigned with Republican gubernatorial candidate Doug Mastriano, the presumed frontrunner who has pushed the lie that Trump won the 2020 election. And she emphasized her anti-abortion position in describing her personal story as the daughter of a girl who had been raped.
This week, Barnette reiterated her opposition to Mitch McConnell as Senate Republican leader, while he was visiting Ukrainian President Volodymyr Zelensky with a GOP US Senate delegation in Kyiv Saturday, and criticized Oz for not explicitly objecting to a $40 billion bill in aid for Ukraine. "America First," she tweeted.
She won endorsements from socially conservative groups like Susan B. Anthony List and CatholicVote, and the anti-tax organization Club for Growth, which is spending nearly $2 million on her behalf.
Janet Shearer, 76, said she's 75% sure she's going to vote for Barnette in the primary. "She tells it like it is and she's a fighter and she loves Trump -- and I love Trump," Shearer said.
But sitting one table over, Bill McCoach, 66, said he thinks Barnette's whole candidacy is a "scam."
"She's part of the left. She's lying," McCoach said.
Several other Republicans echoed McCoach's skepticism, saying they don't know much about Barnette but have started hearing negative things about her in the past week.
Earl Olinger, 68, said he initially liked Barnette, but changed his mind when he saw a TV ad this week that accused her of being "against Trump."
"I'm a big Trump guy. So yeah, if you're against Trump I have a little problem with that because everything he did was good by my standards," Olinger said.
Barnette's advance has worried Oz, McCormick and also Trump, who said in a recent statement that she would not be able to win the general election. This week, a super PAC supporting Oz released an attack ad misleading viewers about her views on Black Lives Matter and systemic racism among police officers. Bob Gillies, Barnette's campaign manager, told CNN that her words were taken completely out of context to make it appear she supported BLM even though she had been on record opposing it. "You need to play the whole video," he said.
Allies and advisors for McCormick, who went to West Point and earned a Bronze Star while serving in the first Gulf War, have raised questions about Barnette's military service, including how she was discharged from the Army.
Barnette also has a history of anti-Muslim and anti-gay statements; Oz has called some of her past tweets "clearly homophobic" or "Islamophobic."
McCormick told CNN that he "didn't anticipate anything quite like" Barnette's unexpected ascent, in part because he has never run for office before. He also told the MAGA base in a podcast with former Trump chief strategist Steve Bannon that he has "no allegiance" to McConnell and would oppose the Ukraine bill.
Asked about Barnette, Oz replied, "The real question for a lot of voters is should they roll the dice?" He then accused the Club for Growth of "turning Kathy into a pawn in a fight with President Trump."
"Funny things happen in multi-candidate races," Toomey told CNN when asked about her polling surge, adding, "There's a lot ... the voters don't know about her."
Barnette's rise in the polls has disrupted a primary race that has been dominated for months by a bitter fight between Oz and McCormick. Honor Pennsylvania, a super PAC backing McCormick, spent $17 million on ads almost exclusively attacking Oz before targeting Barnette this week.
In the ugly Senate primary, McCormick has accused Oz of being a "Hollywood liberal" who had "dual loyalties" because he was a dual US-Turkey citizen. Oz, meanwhile, has accused McCormick of being beholden to China, airing an ad warning voters about McCormick's financial investments in the country to the sound of a banging gong.
Oz on Saturday dismissed attacks on his ties to Turkey, including from former Secretary of State Mike Pompeo, who held a press conference with McCormick's campaign last week raising questions about Oz's "connection to the Turkish government." Oz was born in the US, and has said he still has dual citizenship to help take care of his mom, who has Alzheimer's, in Turkey, but would renounce his Turkish citizenship if elected.
"It's a distraction, purely partisan," Oz said in response to a question from CNN.
McCormick is still defending himself from attacks that he is too cozy with China. He spoke favorably of China as a top Treasury Department official in the George W. Bush administration and was CEO of the massive hedge fund Bridgewater when the company raised $1.3 billion for a new private fund in China. At a recent campaign event in Lititz, Pennsylvania, McCormick compared himself to Trump and said that a small portion of his global business was in China.
"By the way, that's a lot like President Trump, who did business in Russia and China and other countries before he came in office," McCormick said at a campaign event on Friday. "No one has the credentials and the toughness to go toe to toe with China like I do."
This story has been updated with additional details.