Now, with about two months until Election Day, that congeniality has faded, with Oz and his campaign recently directing a flurry of personal and policy attacks at Fetterman — including accusing the Democrat of either withholding information about his health or being afraid to debate.

“I have empathy for what John Fetterman is going through, yet it’s still incumbent upon him to be honest with us, about what he’s able to do and either answer difficult questions about what I think is a far-left radical position on a lot of issues, or be honest about the health problems that you’re facing,” Oz said at a campaign event this week in the Philadelphia suburbs, a swing area in one of the fall’s most consequential Senate battlegrounds.

After enduring a relentless stream of broadsides from the Fetterman campaign during the summer over his wealth, celebrity status and longtime New Jersey residency — mostly in the form of online trolling aimed at portraying him as an out-of-touch opportunist — Oz and his allies have shifted to a more aggressive posture, countering with a sudden volley of criticism aimed at the Democratic lieutenant governor.

It’s part of a strategy some Republicans see as a course correction for a floundering campaign that fell behind Fetterman in the polls and alarmed some GOP leaders. Oz is also working to lock down support from across the Republican Party — a challenge that has loomed over his bid since a bruising primary he narrowly won. In the past week, he has appeared at events with Republicans from across the party spectrum, from former president Donald Trump to his ex-primary challenger, David McCormick, to former U.N. Ambassador Nikki Haley.

“It has taken awhile for Dr. Oz to consolidate Republicans; that’s the first step, and then you have to work on improving your image and then you go after your opponent,” said Sen. Patrick J. Toomey (R-Pa.), who joined Oz on the trail this week. Toomey, whose seat Oz is running to fill, added: “Some of these things got started a little later but they are well underway now, and I think this race is right now nearly within the margin of error. I think [Oz] has a very good shot at winning this.”

This week, Oz appeared to try to distance himself from the far-right wing of his party without alienating a base still loyal to Trump. He said he would have voted to certify the 2020 election results, but would not have voted to convict Trump over his role in the Jan. 6, 2021, attack on the U.S. Capitol by a pro-Trump mob. Toomey was among seven Republican senators who voted to convict Trump.

The Pennsylvania contest is considered by both parties essential to winning control of the upper chamber of Congress next year. Over several events this week, Oz has sought a more defined presence in the race, after keeping a lower profile over the summer months. Yet not everyone who attended Oz’s town hall here Thursday was fully sold on his candidacy, underlining the uncertainty around his ability to win over base voters and persuade swing voters after a sluggish start.

Kathy Finan, 63, had voted for Kathy Barnette in the primary, picking a far-right candidate who ran in close alignment with Trump’s movement, even as Oz had the 45th president’s endorsement. “I don’t know enough about his positions,” she said, adding that “he hasn’t been very visible to me, so yes, I’m interested in what he has to say, what are his top items, what are his issues.”

At the event, held inside a catering hall in a Republican-friendly slice of Delaware County — a vote-rich battleground that chose President Biden over Trump in 2020 by less than two percentage points, but in 2016 picked Trump over Hillary Clinton by an even slimmer margin — Oz stood with Haley on Thursday encircled by voters. The crowd was mostly White seniors.

Oz, who for 13 years hosted a medical talk show, worked the crowd with ease. He kept chatting as he placed a blood pressure cuff on Haley to see whether the issues they said are plaguing the country would make hers rise (it didn’t). He acted out a mock debate, peppering an imaginary Fetterman with questions about crime. At the end, he took a few friendly questions from the crowd.

“I would argue you’re the most radical candidate for the Senate in Pennsylvania ever and maybe the most radical candidate in any contested race in the whole country,” Oz said in his pretend debate remarks.

Oz and his allies have ramped up attacks over comments Fetterman has made about reducing the prison population and giving felons second chances. Oz has spoken in generalities about supporting law enforcement and stopping crime. He said Thursday that people with substance abuse disorder needed “tough love” in detox facilities, not “free heroin injection zones.” Fetterman has advocated for supervised injection sites.

“As Mayor of Braddock, John worked with the police and the community to confront the gun violence and crime,” Fetterman spokesman Joe Calvello said in response to Oz’s attacks.

Fetterman said this week that he was committed to debating Oz once before the election, sometime in October, but that his campaign was still sorting out the details, given his lingering auditory and speech limitations from his May stroke — including the possibility of using closed captioning. The Oz campaign has said the lack of specificity is insufficient.

“There’s pretty much consensus that they’ve turned to offense. It feels like Fetterman is on significant defense for the first time. I’m more bullish on Pennsylvania than at any point,” said a Republican operative with a close eye on the race, who, like others interviewed for this story, spoke on the condition of anonymity to talk more openly about the race.

The Democratic nominee was off the campaign trail for much of the summer and has eased back into events slowly with limited direct public interactions. At times, he has struggled with his speech, but the Fetterman campaign has insisted that he is up to the job of being a U.S. senator.

In late August, Oz’s campaign released a sarcastic list of suggested debate accommodations for Fetterman, including saying “at any point, John Fetterman can raise his hand and say ‘bathroom break!’ ” This came shortly after one Oz aide mocked the Democrat for not eating vegetables before his stroke. The National Republican Senatorial Committee continues to accuse Fetterman of “lying” about his health.

Fetterman suffered a stroke just days before the May primary. At the time, his campaign did not publicly disclose some major details about his health. Only later did he disclose the severity of his illness as well as a previously unrevealed heart condition and the fact that he had not taken prescribed medication.

At the Thursday event, Haley offered her sympathies to Fetterman, but added: “He owes you to be honest. He owes to step up and show everyone what his capabilities are. If he can’t live up to 110 percent of the job, he should have the courage to step out and say, ‘I can’t do it.’ ”

Calvello called Oz “a total and complete fraud,” and added that Fetterman “is having an honest conversation about health, one that thousands of Pennsylvanians have probably had with their own families.”

Republicans are trying to puncture the persona Fetterman has created of a straight-talking, anti-establishment man of the people who will upend Washington norms in an oversized sweatshirt and cargo shorts. That pitch appeared to be working for much of the summer. In mid-August, a Franklin & Marshall College poll found Fetterman leading 43 percent to Oz’s 30 percent, with 20 percent undecided.

Other recent polls have shown that Fetterman continues to lead Oz, but by varying margins. Republicans say they see an opportunity for Oz to gain ground over the race’s final weeks, particularly if Fetterman does not have an active presence on the campaign trail.

“I feel sorry for him, for anybody who had a stroke, and he should be smart enough to bow out,” said Antone Ambrosino, 77, who sat in the back row at Oz’s town hall Thursday, wearing a red “Make America Great Again” cap. “If he can’t debate Dr. Oz, how is he going to debate someone on the Senate floor?”

Isaac Arnsdorf and Scott Clement contributed to this report.