Even Sen. JD Vance’s allies realize the relative political newcomer has taken a huge leap that was bound to run into some early stumbles.

The Ohio Republican is the most politically inexperienced GOP vice-presidential nominee in almost 90 years. He’s run in just one election for any political office.

“You know, he’s gotten shot out of a cannon. It’s like going from zero to 60 in terms of intensity, publicity, scrutiny, all that stuff,” said Sen. Josh Hawley (R-Mo.), an early supporter of Vance in his 2022 Senate campaign.

“Enduring the demonization of the national media is never easy,” Sen. Ted Cruz (R-Tex.), who embraced the antiestablishment posture a decade before Vance arrived in the Senate. “I will say this, if the New York Times were praising JD Vance, I would view that as a much, much bigger problem.”

Some of his Senate Republican colleagues think that’s understating the firestorm in which Vance now finds himself.

With Vance thrust onto the national stage less than a month ago, they’ve been forced to defend resurfaced comments from his pre-Senate days. There’s the 2021 clip of him on Fox News’s lashing out at “childless cat ladies” and then a far-right podcast in which he called for a higher tax rate on adults without children. Some of Donald Trump’s allies counseled that Vance wasn’t an ideal choice because he doesn’t expand the GOP coalition.

On Wednesday, Sen. Lisa Murkowski (R-Alaska) lashed out at her colleague’s remarks. “It was offensive to me as a woman. Women make their own determinations as to whether or not they’re going to have children,” she told reporters.

On Tuesday, when asked about her thoughts on Vance’s comments, Sen. Susan Collins (R-Maine) reminded reporters she hasn’t endorsed Trump or Vance. Nor has Murkowski.

At 39, Vance is the second youngest of the 100 senators. His selection as Trump’s running mate has prompted deeper looks at his years spent as a best-selling author who served as provocateur on his many cable TV appearances.

In his early 30s, during his anti-Trump era, Vance compared Trump to “cultural heroin” and found the GOP presidential contender to be “noxious.” By the time he launched his first campaign three years ago, Vance kept up his firebrand routine in his bid to convince the ex-president of his newfound MAGA embrace.

That’s when he uttered comments about women and children. Rather than retracting them, Vance doubled down in an interview last week on Megyn Kelly’s podcast, saying his comments were “true” while arguing he has “nothing against cats.”

Those types of comments help in a low-turnout GOP primary, but Senate Republicans are not surprised they have caused a stir and led to a quick backlash against Vance (according to an ABC/Ipsos poll released last weekend, Vance’s unfavorable ratings spiked eight points to 39 percent in a week). They say that Vance is quickly learning that the national spotlight is far more intense than the Senate one.

“What you learn very quickly here, and you can only learn through time, is that even if your comments were meant in jest or they were hyperbolic — they weren’t really intended [to be offensive] — in this league, you don’t get a bye week. Everything, everything, you say gets parsed,” said Sen. Thom Tillis (R-N.C.), from the party’s traditional conservative wing.

“That can only come from having experienced a lot of sunrises and sunsets on the road,” Tillis added, “and that would be the one thing that JD can’t possibly have. Because he’s only been in the public eye as an elected official for two years.”

“When you are going from cable TV to podcasts, it’s part of surfing out there,” said Sen. Lindsey Graham (R-S.C.), who privately campaigned to get Trump to choose another nominee.

Now that President Biden, 81, has withdrawn from the race, Republicans have braced for more scrutiny over the gravitas of their vice-presidential pick given that Trump, 78, faces similar questions about his age and capabilities to serve a four-year term.

Since World War II only one other major party nominee has chosen a running mate with such little experience.

By August 1972, Sargent Shriver had served as the first Peace Corps director and as ambassador to France, and had led a White House anti-poverty program, but had never run for political office when Democrats turned to him. His nomination only came out of dramatic necessity, however, when the original choice — then-Sen. Thomas Eagleton, with 12 years of statewide elective office under his belt in Missouri — withdrew following revelations about his mental health.

Otherwise both parties have tended to use the vice-presidential pick as a balancing act, either for regional or ideological balance or for reassurance of the No. 2 being ready step into the job, according to Donald A. Ritchie, the Senate’s historian emeritus.

Think then-Sen. Joe Biden (D-Del.) in 2008, with 36 years of experience, getting tapped by Barack Obama after less than four years in the Senate. Or Richard Cheney (R-Wyo.), with 12 years in Congress and four as defense secretary, getting the nod from a young Texas governor, George W. Bush, in 2000.

“They’ve all had enough experience to claim to be ready to become president if necessary, which is really the only justification for the job,” Ritchie said.

Each party has at times nominated an elder statesman at the top of the ticket, prompting a younger vice-presidential pick, but even those No. 2 selections had more experience than Vance.

In 1988 George H.W. Bush, then the sitting vice president, chose then-Sen. Dan Quayle (R-Ind.) as his running mate, leading to tough scrutiny of Quayle’s credentials. Yet Quayle had served almost eight years in the Senate and four years in the House. In 2020 Joe Biden, 77 at the time, chose Kamala Harris (D-Calif.) after less than four years in the Senate — but she also had served six years as state attorney general and eight years as district attorney.

In 2008 John McCain (R-Ariz.), then 72, chose the 44-year-old Sarah Palin and sparked weeks of controversy. Palin had served as Alaska governor for 19 months and served as mayor and city council member for years before that.

Vance’s close allies acknowledge that he provides no political balance for Trump heading into November and view his selection as entirely about being a junior governing partner in the White House.

“There’s risk with anybody. I mean, there’s always risk,” Hawley said. “I think Trump wants somebody who he can count on 100 percent. And who he knows is going to be with him 100 percent of the time. And I think JD will be. And I think that’s why he chose him.”

Cruz said that Vance, through his childhood in Ohio and Kentucky, understands the governing appeal for Republicans no longer resides in country clubs and corporate boardrooms.

“I believe the Republican Party has become a blue-collar party. And I think JD gets that in his gut, and that’s important. I think the ferocity of the left-wing media going after him, demonstrates that JD is touching a nerve,” Cruz said.

Still, Vance has not demonstrated many political skills thus far in his career, aside from becoming close friends with Donald Trump Jr. and some far-right conservative billionaires.

His 2022 Senate campaign was stumbling along until Vance won a late endorsement from former president Trump, and even then he eked out a plurality win with less than 33 percent in a crowded field.

It was a banner year for Ohio Republicans, with Gov. Mike DeWine (R) ringing up a 25-percentage-point blowout. DeWine helped four other Republicans running for statewide offices to easy wins by margins of 17 to 20 points.

Vance’s campaign, however, was a dud.

Slow to mobilize or raise money, Vance won by just six percentage points. His Democratic opponent, Tim Ryan, outspent Vance by a more than 4-to-1 margin in advertising, according to a Democratic estimate.

Outside Republican groups rushed $34 million into the race, publicly admitting it was “an unexpected expense” and money they could have spent in races they narrowly lost, like Nevada.

Graham acknowledged the rumors that he preferred other potential nominees such as Sen. Marco Rubio (R-Fla.) for Trump’s pick.

“We tend to want people we know, that we have a close relationship with. I know Marco very well and so I have an affinity for that,” he said.

Graham agreed with Hawley that, as a governing partner to Trump, “the ‘America First’ agenda would be in good hands with JD.”

First, he has a key bar to clear.

“The vice president just needs to be seen as somebody competent and capable,” Graham said.

Has Vance demonstrated competence yet?

“The debate will be his chance to prove to people he’s competent and capable,” Graham said. “And I think he’ll have a good debate because he’s really, really smart.”

Senate Republicans believe Vance’s intelligence — Ivy League education, best-selling author, provocative thinker — is not in question.

“JD is a smart guy. He’s just needs to be a quick study on it,” Tillis said.

Trump fell into an indirect slight of Vance when he was asked Wednesday whether his running mate was ready on “day one” to serve in the White House.

“Historically, the vice president, in terms of the election, does not have any impact. I mean, virtually no impact. You have two or three days where there’s a lot of commotion,” Trump said at the National Association of Black Journalists conference.

He said voters would not consider Vance when casting their ballots.

“You’re not voting that way,” he said. “You’re voting for me.”