WASHINGTON (AP) — It’s hard to refer to someone as “Hitler” and end up in their good graces, let alone potentially become the person they choose to help lead the country.

But Ohio Sen. JD Vance’s shifting position on Donald Trump over the years from one-time critic of the former president to staunch ally is a metamorphosis shared by many of Trump’s potential running mates.

It’s not unheard of for a running mate to move beyond past disagreements with a presidential candidate. Joe Biden had a notably barbed exchange with Kamala Harris in 2020 when both were seeking the Democratic nomination. Harris confronted Biden over comments in the 1970s about school busing, telling him during a debate that she did “not believe you are a racist” even though he’d made “hurtful” comments about being able to work during his career even with segregationist senators. Biden picked her to be his vice president anyway.

But the shift is more striking for Trump’s potential running mates, in some cases requiring them to abandon long-held policy positions and recant vehement criticism.

Here’s a look at some of those shifts:

JD Vance

In a 2016 interview with Charlie Rose while promoting his book “Hillbilly Elegy,” Vance called himself “a Never Trump guy” and said of the soon-to-be-president, “I never liked him.”

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He told NPR that year, “I can’t stomach Trump. I think that he’s noxious and is leading the white working class to a very dark place.” He wrote an op-ed for The New York Times titled: “Mr. Trump Is Unfit For Our Nation’s Highest Office.”

Vance said he didn’t vote for Trump in 2016 and his former roommate shared images of a text message Vance sent him that year in which he called Trump “cynical” and said he could be “America’s Hitler.”

But by the time Vance launched his campaign for the Senate in 2021, his views were closely aligned with Trump’s. He met with the former president and quickly won his endorsement, gaining a crucial boost in the Republican primary.

Vance has said he “was wrong” about Trump. In an interview this month on Fox News Channel, he was asked to explain his past criticism.

“I didn’t think he was going to be a good president,” Vance said. “He was a great president. And it’s one of the reasons why I’m working so hard to make sure he gets a second term.”

Even as a freshman, Vance has stood out in the Senate as one of Trump’s fiercest defenders and as an emerging voice on foreign policy. Aligning himself with the party’s more populist wing, Vance has fiercely opposed additional aid to Ukraine and even traveled to the Munich Security Conference earlier this year to make the case against it.

As Vance’s name rose to the top of Trump’s list of potential running mates, he notably embraced positions that contrast with former Vice President Mike Pence, telling ABC News in an interview that he would not have immediately certified the results of the 2020 election.

He’s also said he was “truly skeptical” that Pence’s life was in danger on the Jan. 6, 2021 attack on the Capitol and called the bipartisan committee that investigated the attack “a sham.”

Trump publicly and privately pressured Pence to overturn Biden’s 2020 election win during the congressional certification on Jan. 6, 2021, something Pence had no power to do. Trump’s pressure campaign was a motivating factor in the violent mob assault on the Capitol, many chanting “Hang Mike Pence” as they fought their way into the building and searched for lawmakers. The House Jan. 6 committee found the mob came within 40 feet of Pence as he was hastily evacuated from the Capitol.

Pence has pointedly refused to endorse Trump for another term in the White House.

Marco Rubio

Some of Florida Sen. Marco Rubio’s harshest comments about Trump came as they sparred during the 2016 Republican race for president. Trump started calling him “Little Marco” and mocking him. Rubio responded by insulting Trump’s makeup and the size of his hands.

Rubio also called Trump a “con artist,” and “the most vulgar person to ever aspire to the presidency.”

Earlier this year, when ABC News played back some of Rubio’s comments from 2016, he responded by saying, “It was a campaign.”

He made similar comments in a recent interview with CNN, saying “That is like asking a boxer why they punched somebody in the face in the third round. It’s because they were boxing.”

Their relationship improved dramatically while Trump was in the White House. And as Trump has campaigned for the presidency a third time, Rubio has cheered his proposals.

In the Senate, Rubio had long been a prominent voice on immigration and was a key member of a group that worked on a 2013 bill that included a path to citizenship for millions of people in the country illegally. Now, Rubio says he supports Trump’s plan to deploy the U.S. military to deport those in the country illegally.

“We are going to have to do something, unfortunately, we’re going to have to do something dramatic,” Rubio said in a May interview with NBC.

When shown clips of his comments in 2016 in which he said Trump’s plans for mass deportations were not realistic or workable, Rubio said, “the issue has completely changed.”

The senator said the number of people coming into the U.S. had vastly increased and called it “an invasion of the country.”

Doug Burgum

Burgum was one of more than a dozen Republicans who ran against Trump in the 2024 presidential primary, but he dropped out in December and endorsed Trump before voting began.

Before that, the North Dakota governor had rejected the idea of partnering with Trump.

In an interview last July on NBC’s “Meet the Press,” Burgum, a businessman, was asked if he’d ever do business with Trump, and responded, “I don’t think so.” He added, “I just think that it’s important that you’re judged by the company you keep.”

The next month, he told CNN in an interview that he would not serve as Trump’s vice president.

Like many other Republicans, Burgum was critical of Trump in 2016, when the “Access Hollywood” video was released in which Trump bragged about grabbing women by the genitalia without their consent. Burgum, then a Republican candidate for governor, issued a statement calling Trump’s comments “offensive, wrong, and unacceptable.”

Burgum this year has become an enthusiastic champion of Trump and has leveraged his profile as a wealthy businessman and governor versed in energy policy to help the Republican secure millions in fundraising, especially from high-dollar donors.

Elise Stefanik

When the New York congresswoman was first elected in 2014, she was known as a moderate Republican with ties to the party’s establishment, having worked in George W. Bush’s White House and on the presidential campaigns of Minnesota Gov. Tim Pawlenty and later Mitt Romney, serving as an aide to former House Speaker Paul Ryan.

In 2016, she initially supported Ohio Gov. John Kasich’s campaign. When Trump was the party’s nominee, she didn’t say his name, only saying she would “support my party’s nominee in the fall.”

She became a more vocal supporter as the election neared but made it clear she disagreed with him at times, criticizing his comments on the “Access Hollywood” tape and disagreeing with his position on NATO, his decision to withdraw from the landmark Paris climate agreement and his ban on travelers from predominantly Muslim countries, for example.

Those disagreements faded over the years. Stefanik abruptly emerged as one of Trump’s most outspoken defenders during his first impeachment in 2019, and it’s a role she’s embraced ever since. When Republicans ousted former Rep. Liz Cheney from leadership over her criticism of Trump and his efforts to overturn the 2020 election, it was Stefanik they chose to take her place.

In her role as House GOP conference chair, Stefanik has railed against Trump’s criminal conviction in New York, championed his policy proposals and echoed his language about Jan. 6, falsely declaring those imprisoned for the attack to be “hostages.”

Her loyalty to Trump stood out in 2022, as the former president’s esteem within the party had deflated after he was absorbing blame for weaker-than-expected results in the midterm elections. Stefanik announced days after the election that she was endorsing Trump for president in 2024 — an announcement that came before Trump even said he was running.

Earlier this month, when local reporters in her New York district asked her about her past criticisms of Trump, Stefanik repeatedly professed her support for the former president.

“I’m proud to have voted for him and supported him in 2016 on the ballot,” Stefanik said, according to WAMC radio in Albany. “I’m proud to be his strongest ally in Congress. And I’m proud to continue to work, no matter how the vice presidential situation shakes out, I will continue to be a fighter for this district and supporting President Trump who has a proven record of delivering results.”

Tim Scott

In 2016, the South Carolina senator initially backed Rubio in the presidential race and that same year excoriated Trump for his reluctance to condemn the Ku Klux Klan.

“If Donald Trump can’t take a stand against the KKK, we cannot trust him to stand up for America against Putin, Iran or ISIS,” said Scott, the Senate’s only Black Republican.

He likewise criticized Trump for his attacks on a judge’s Mexican heritage in 2016, calling it “racially toxic” and said the “Access Hollywood” comments were “indefensible” and “disgusting.” He still supported Trump in the 2016 election, calling him the “lesser of two evils.”

Scott also criticized Trump after his comments equivocating about the 2017 white nationalist rally in Charlottesville, Virginia, saying that his “moral authority” was “compromised.”

He met with Trump at the White House after. In an interview on Fox News Channel on Thursday, Scott said that he shared his perspective with the then-president in that meeting and from then on they worked to “find solutions together.”

“It was the Charlottesville incident that made our relationship what it is today,” Scott said.

Though he ran against Trump in the 2024 GOP primary, Scott dropped out and endorsed the former president, becoming one of his most enthusiastic cheerleaders.