WASHINGTON — Nikki Haley dropped out of the GOP presidential primary more than two months ago, but her zombie candidacy is still drawing a significant number of votes in late-season contests — enough to make Republicans anxious over what this could mean for their presumptive nominee, Donald Trump, and whomever he chooses as his running mate.

Voters who spurned Trump might be brought back into the Republican fold if he picks a centrist vice presidential candidate in the mold of Haley, the ex-South Carolina governor and Trump’s first United Nations ambassador, who seems to have zero interest in joining his ticket. But it’s not clear whether any of the people currently on his veep shortlist — mostly MAGA senators and governors — can capture the voters who want to move on from Trump.

Republicans floated as possible running mates include Sens. Marco Rubio of Florida, Tim Scott of South Carolina and J.D. Vance of Ohio, as well as Rep. Elise Stefanik of New York, North Dakota Gov. Doug Burgum and South Dakota Gov. Kristi Noem — even after Noem was pilloried for describing in a new book how she killed her aggressive hunting dog. None of them is seen as a likely vessel for winning over Haley’s staunchest fans.

GOP senators suggested that going after disaffected Haley voters should be a priority for Trump, who is narrowly leading in swing-state polls but fighting legal battles that make his political future uncertain.

“I think the population we need to be going after is this 17% of people that are not voting for President Trump in a primary even though Nikki is not even in the primary,” Sen. Roger Marshall (R-Kan.) said Wednesday, referring to Haley’s share of the vote in Pennsylvania’s GOP primary last month. “I think he needs to bring a person that’s going to complement him and bring those people to the table.”

Marshall floated former Kansas congressman and Secretary of State Mike Pompeo as someone who could fit those qualifications.

“I think there’s a group of Republicans out there that will play the long game,” he added. “They want to know who’s going to be the president after President Trump. So whoever he chooses is going to be the betting-odds favorite to be the next president.”

Sen. Thom Tillis (R-N.C.) urged the Trump campaign to pay attention to this week’s Indiana primary results and “see what demographic chose Nikki Haley over the president.”

“I’d be instructed by that in my solution,” he added.

In Indiana on Tuesday, Haley won roughly 1 in 5 GOP primary voters, underscoring the discontent among committed Republican voters with the former president, who faces 88 felony charges. About one-fifth of Republican primary voters in the swing states of Arizona, Wisconsin, and Pennsylvania also cast a ballot for someone other than Trump.

Sen. Todd Young (R-Ind.), an anti-Trump Republican, said that the primary results in his home state show how there is “still a very sizable portion of the Republican Party that’s insisting on a candidate who they can be proud of, on account of their character attributes and who promote a policy agenda consistent with basic [President Ronald] Reagan-era principles.”

Haley, for her part, has shown no sign of getting back on the Trump train anytime soon. Before she dropped out of the race in March, she excoriated her former boss over his conduct in office and his mental state, calling him “diminished” and “unhinged.” And she has declined to endorse his campaign, leaving Trump to suffer repeated embarrassments in primary contests across the country.

The people voting for Haley tend to be more affluent, better educated than Trump voters, and active enough in politics to bother casting a ballot in a long-over presidential primary. One recent exit poll found that many are likely to back President Joe Biden over Trump in November. These voters are largely clustered in swing counties surrounding major metro areas — like the Philadelphia and Detroit suburbs — where parties battle for the independent voters who decide presidential elections.

Adrian Hemond, a Michigan Democrat who founded a bipartisan political consulting group, said that Trump needs to find a way to reassure skittish Haley voters if he wants to win in the Upper Midwest.

“These people are still clearly Republicans. They’re voting in Republican nominating contests. … They’ve just got beef with the former president,” Hemond said. “He needs to give them some sort of permission structure to vote for him so they feel like there will be an adult in the room, and there will be someone who can replace him if he’s not capable of continuing in office for whatever reason.”

Hemond said Trump would be well advised to pick a running mate who has a record independent of MAGA, like Burgum, who didn’t compete against Trump in the primary long enough for things between them to get nasty.

“There’s going to be a lot of pressure on the former president not to pick a Republican senator, and at minimum not pick a Republican senator from a state that’s at all competitive or a state where the governor cannot appoint a replacement,” he said.

But Vance, a top Trump ally who hasn’t been shy about expressing his interest in the VP job, rejected the notion that the ex-president needed to worry about the Haley protest vote.

“Attracting Nikki Haley voters should not be the focus of the vice presidential pick, but certainly you want somebody who’s going to broadly appeal as much as possible to the country,” Vance said. “You don’t want to alienate anybody, but I don’t think [the] Nikki Haley bloc is big enough to be the focus.”

Some pollsters and analysts have backed Vance’s analysis, noting that Haley’s primary voters make up a relatively small portion of what will be a much larger general electorate and pointing to Trump’s advantage with less-engaged voters as a more important factor for November.

In modern history, presidential campaigns have tended to pick running mates in hopes of broadening a candidate’s appeal — either to a geographic area or a particular group of voters. In the 2016 election, for example, Trump picked then-Indiana Gov. Mike Pence as a way to curry favor with social conservatives and evangelicals, influential GOP constituencies that initially hesitated to support a thrice-married New York real estate mogul. In 2008, Barack Obama selected Biden, then a veteran senator, in part because of his deep foreign policy experience.

This time, Trump is being urged to consider candidates who can appeal to wayward Republicans and independent voters turned off by his behavior and obsession with conspiracy theories, including those involving the veracity of the 2020 presidential election.

“Typically, the candidate looks for somebody who will broaden the base of support and appeal, not somebody who is exactly like them or attracts the same constituency,” Sen. John Cornyn (R-Texas), who is running to succeed Sen. Mitch McConnell (R-Ky.) as the top Senate Republican, told HuffPost on Wednesday.

He added, “I’d like President Trump to win, and I think the best formula for him to win would be to broaden that base by picking somebody who would bring that to the table.”