There are other factors Trump is looking at as well, as NBC News has previously reported, including the candidate’s stance on abortion, how prolific a fundraiser they are and if they match up well against Harris in a debate.

But past anti-Trump remarks haven’t made much of a dent. As NBC News reported Wednesday, the front-runners are currently North Dakota Gov. Doug Burgum and Sens. Marco Rubio of Florida, J.D. Vance of Ohio and Tim Scott of South Carolina, though sources cautioned that the shortlist is fluid.

When campaigning against Trump in 2016, Rubio warned that in the years to come, there will be “many people on the right, in the media and voters at large, that are going to be having to explain and justify how they fell into this trap of supporting Donald Trump.” He said Trump was “reckless and dangerous” and would do “damage to America.”

Vance described himself in 2016 as “a Never Trump guy,” calling Trump “an idiot,” “noxious” and “reprehensible.”

In 2017, Scott took issue with Trump’s handling of the white nationalist rally and violence in Charlottesville, Virginia, lambasting the then-president for drawing an equivalence between the protesters and counterprotesters and saying there was “no question” Trump “compromised” his “moral authority.” What’s more, during his presidential campaign, Scott acknowledged on a debate stage that then-Vice President Mike Pence did the right thing on Jan. 6 by refusing to reject the electors affirming Biden as the duly elected president.

Burgum, who has spent less time in the national spotlight, was reluctant to mention Trump while campaigning against him for president during his short-lived primary run and did not denounce his attempt to overturn the 2020 election results. But the businessman-turned-politician did tell NBC News’ Chuck Todd on “Meet the Press” last year that he wouldn’t want to get into business with Trump.

“I just think that it’s important that you’re judged by the company you keep,” Burgum said before Chuck Todd asked him to clarify, “You just wouldn’t do business with him?”

“No, I wouldn’t,” Burgum said.

The North Dakota governor was always reluctant to say Trump’s name when campaigning against him in the GOP primary and would never denounce Trump’s attempt to overturn the 2020 election results.

Other potential running mates also have such moments in their past. Rep. Elise Stefanik, R-N.Y., who has become a die-hard Trump loyalist, once called him a “whack job” in a message obtained by The New York Times. She also said in a radio interview that Trump was “insulting to women” and predicted Trump’s candidacy would have negative effects on the GOP’s ability to appeal to female voters.

In a recent interview with Fox News’ Shannon Bream, Stefanik hit back at Bream when the anchor mentioned the New York Republican’s years-old remarks about the former president.

“It’s a disgrace that you would quote The New York Times with nameless, faceless false sources,” she said.

They’re hardly alone on the right. Trump has for years rehabilitated his relationships with Republicans who once offered stinging criticism of him only to later patch things up and tightly embrace Trump in public.

“No one’s clean on this,” said one Trump-aligned Republican operative close to a potential VP choice, noting criticisms lobbed by contenders in past cycles, including by Republicans who challenged him for the party’s presidential nomination.

This person also mentioned that Trump nodded to Vance’s past critiques during a recent Republican National Committee retreat at Mar-a-Lago. Trump said of Vance: “You know he wasn’t a supporter of mine. He was saying things like, ‘The guy’s a total disaster!’”

“I think it’s always in the back of his mind,” this person added. Yet they said the real loyalty test for Trump would not be whether someone was ever critical of him, but that “once Trump became president and in moments that didn’t just matter for VP, where were you?”

“That shows loyalty,” this person said.

Trump would not be the first major party nominee to tap a prior critic. President Ronald Reagan selected George H.W. Bush to serve as his running mate after Bush offered blistering criticism of his then-rival in the 1980 GOP primary. Biden too chose Harris after that headline-grabbing debate moment. But perhaps no major party’s presumptive nominee in modern times has considered such an extensive list of past critics for the role.

The current contenders have spent years in some cases working to overcome their past criticism. Vance expressed regret over his remarks and built a relationship with Trump ahead of the former president’s endorsement of him in a hotly contested Senate race in Ohio in 2022, becoming one of his staunchest Senate allies after his election that fall.

Scott built a strong relationship with Trump working on a number of policy issues and met personally with him following Charlottesville, a meeting that led Scott to say Trump had “obviously reflected” on his remarks.

Burgum, after having little relationship with Trump prior to his presidential run, has quickly appeared alongside him at multiple events and attended his Manhattan trial, which Vance did as well.

Rubio, meanwhile, buried his differences with Trump after the 2016 election and worked with him on policy. Although he said Trump bore “responsibility for some of what happened” on Jan. 6, he blasted his second impeachment trial as “stupid” and voted to acquit him. Rubio also mocked the House select committee tasked with investigating Jan. 6.

Stefanik was a bulldog defender of Trump during his first impeachment trial, a role she has relished in the years since.

How they would handle the results of this upcoming election has also become a point of emphasis. In 2020, Rubio voted to accept the electors affirming Biden’s win, but on NBC News’ “Meet the Press” last month, he would not commit to accepting this fall’s results if Biden wins. Scott, who also affirmed the 2020 results and said at the outset of his presidential bid last year that he would not overturn an election he lost, similarly would not make an unequivocal commitment last month.

“I don’t think Trump cares all that much if you were critical of him in 2015, 2016 or early 2017,” a pro-Trump operative said. “Go look at some of his biggest allies — a lot of them were critical. A bigger issue for him are the people who bailed on him after Jan. 6 or people that went with DeSantis over him.”

“You know who you don’t see on the VP shortlist? Anyone who backed DeSantis,” this person added, pointing to Iowa Gov. Kim Reynolds and Oklahoma Gov. Kevin Stitt.

Steve Bannon, the former Trump White House aide and prominent right-wing media personality, said he did not think those past criticisms would hold much weight with Trump now, pointing specifically to how Vance and Trump worked all of that out during the Senate primary in 2022.

Bannon — whom a judge on Thursday ordered to report to prison by July 1 to begin serving his four-month sentence for contempt of Congress — said the real battle over the VP slot is between Trump loyalists who like the contenders he’s considering, and donors who want former U.S. Ambassador Nikki Haley on the ticket.

Bannon predicted “a showdown” at the convention over this, because donors “believe they can force the issue of who’s the VP.”

“And they don’t want the governor of North Dakota,” he said. “They want Nikki Haley.”

Haley, who did say she would vote for Trump late last month, was blistering in her criticism of him toward the tail end of her presidential campaign this year. During a Newsmax interview on Tuesday, Trump said he “was very disappointed in her because she stayed too long.”

“Some people would be very disappointed if I chose her, and possibly some people would be, you know, fine,” he said. “But I beat her by a lot. I mean, I think she was the last one in but that doesn’t mean she did the best job outside of me.”

The longtime Trump ally explained how, for Republicans skeptical of Trump, “all sins were forgiven” if they came on board after the Indiana primary. This time around, this person said, contenders will struggle or hit roadblocks if they have “been off the reservation recently.”

“He’s going to prize vocal support,” this person said. “He’s going to prize people who really had his back on the trials, the payments, he’s gonna prize that stuff in a meaningful way. And so, yeah, [the criticism may be a] tiebreaker, sure. But it’ll be holistic. And there’s a recency component to all of those things people have said or done.”