In Mehmet Oz, Herschel Walker and JD Vance, the Republican party has three celebrities running for Senate in November.

The only problem? At the moment, each of them looks as though they might lose.

Oz, a television stalwart better known as Dr Oz to millions of Americans, is trailing his opponent in Pennsylvania by double digits.

Vance, a bestselling author and conservative commentator, is behind in his race in Ohio, an increasingly red state that many expected Republicans to win. So far the most notable point of his campaign was when Vance appeared to suggest women should stay in violent marriages.

In Georgia, Walker, a former NFL running back, is running close against Raphael Warnock, the incumbent Democrat. But Walker’s campaign has been characterized by a series of gaffes, and this week, more seriously, his ex-wife recalled in a campaign ad how he once held a gun to her head.

The three men’s travails spell out a problem in selecting outsider, celebrity candidates. Each brings name recognition, but in some cases have been unexposed to the media’s glare.

The Pennsylvania Senate race is looking particularly dire for Republicans. According to FiveThirtyEight’s polling average, John Fetterman, the Democratic lieutenant governor, holds an 11% lead over Oz. Among Republicans in Pennsylvania, just 35% say they are “enthusiastic” about Oz’s candidacy, according to a Fox News poll in July, and 45% of Republicans say they “have reservations” about the physician.

Oz’s struggles are significant enough that the National Republican Senatorial Committee is considering diverting money away from Oz’s campaign “to seats that we feel we can win”, Politico reported in July – a dramatic move given the Senate seat was previously held by a Republican.

Oz has decided to try his hand at politics after being a fixture on American television for two decades, initially as a medical expert on the Oprah Winfrey show, then as the host of several of his own shows, including The Dr Oz Show, Surgeon Oz, and Transplant!.

His TV career brought him fame, but scrutiny, too. In 2014 a Senate panel chastised Oz for featuring quack medical products on The Dr Oz Show. The doctor had described various supplements as “magic weight-loss cure”, and “the No 1 miracle in a bottle”, the Senate panel noted, despite no evidence to support the claims.

“I don’t get why you say this stuff because you know it’s not true,” Claire McCaskill, a Democratic senator, said at the time.

In response Oz said of the products, which included green coffee extract: “I recognize they don’t have the scientific muster to present as fact, but nevertheless I would give my audience the advice I give my family all the time, and I have given my family these products.”

If suspicions linger about Oz’s snake oil salesman past, another problem for the GOP is that serious questions have been asked about whether Oz actually lives in Pennsylvania. Oz was a longtime New Jersey resident before, he says, he moved to the Keystone state in late 2020 – specifically into a house owned by his wife’s parents.

Fetterman has seized upon Oz’s residency status by recruiting Nicole “Snooki” Polizzi, from the TV show Jersey Shore, to troll Oz online.

Walker’s campaign seems less doomed. He’s less than three points behind Warnock. But the retelling by Cindy Grossman, Walker’s ex-wife, of how the Republican “held the gun to my temple and said he was going to blow my brains out”, probably horrified some Georgians. Walker has said he struggled with mental health problems during the marriage, and has said he is “accountable” for violence in the relationship.

Before the video aired, Walker’s campaign was hardly running smoothly, with reports that his staff faced a constant struggle to limit the candidate’s public appearances after a string of gaffes and bizarre comments.

Walker has stumbled when talking about his ideas to limit school shootings, and baffled many with comments about the environment, when he claimed that “good air” above the US “decides to float over to China’s bad air”.

He has also suggested in one interview that the theory of evolution is incorrect.

“At one time science said man came from apes,” Walker said.

“If that is true, why are there still apes?”

The Daily Beast quoted one Walker staffer as saying: “He screws up on Fox News where people agree with him, so the idea of him taking an adverse interview or interacting with people who don’t agree with him is a non-starter.”

The Republican leadership might have expected fewer problems from Vance, who is about four points behind Tim Ryan in Ohio. The Hillbilly Elegy author has been a frequent commentator in conservative circles and is a TV regular.

But Vance attracted severe criticism in July, after Vice published footage of him suggesting that people should stay in violent marriages, during a Q & A at a school in September 2021. Speaking about the rise in marriages that end in divorce, Vance said:

“This is one of the great tricks that I think the sexual revolution pulled on the American populace.

“Which is the idea that like: ‘Well, OK, these marriages were fundamentally, you know, they were maybe even violent, but certainly they were unhappy. And so getting rid of them and making it easier for people to shift spouses like they change their underwear, that’s going to make people happier in the long term.’

“And maybe it worked out for the moms and dads, though I’m skeptical. But it really didn’t work out for the kids of those marriages.”

Asked by Vice News why “it would be better for children if their parents stayed in violent marriages than if they divorced”, Vance said he was a victim of domestic violence.

“I reject the premise of your bogus question,” Vance said.

“As anyone who studies these issues knows: domestic violence has skyrocketed in recent years, and is much higher among non-married couples. That’s the ‘trick’ I reference: that domestic violence would somehow go down if progressives got what they want, when in fact modern society’s war on families has made our domestic violence situation much worse. Any fair person would recognize I was criticizing the progressive frame on this issue, not embracing it.”

If the disagreeability, and general incompetence, of the celebrity candidates – all of whom have been endorsed by Donald Trump – has surprised many, it doesn’t appear to have shocked senior Republicans.

Mitch McConnell, the Senate minority leader who has looked on as Trump has effectively taken over the GOP, is among those who seem to have admitted that some of the candidates would struggle in November.

“I think it’s going to be very tight. We have a 50-50 nation,” McConnell said in an interview on Fox News.

“I think when this Senate race smoke clears, we’re likely to have a very, very close Senate still, with us up slightly or the Democrats up slightly.”