The first time President Trump was in the White House, Gov. Gretchen Whitmer of Michigan made no secret of her distaste.

Ms. Whitmer, a Democrat, accused him of not taking Covid-19 seriously enough. And she blamed his rhetoric for what prosecutors described as a plot by several men to kidnap and kill her.

But in Mr. Trump’s second term, Ms. Whitmer has taken a far different approach. She has made repeat visits to the Oval Office. She has thanked Mr. Trump in speeches. And though she often criticizes his policies, she has forged a personal connection with the president and sought areas of agreement, a far more conciliatory strategy than other Democratic governors who are seen as presidential contenders.

That new tack, Ms. Whitmer and her defenders say, has paid off for Michigan with tangible federal assistance after natural disasters, support for the state’s efforts to combat invasive fish and a plan to bring fighter jets to the state. It may also reflect the political reality of Michigan, a swing state that voted twice for Ms. Whitmer and twice for Mr. Trump. But the governor’s pivot has divided Democrats, some of whom openly long for a return to her more pugnacious past.

That shift also hung over Ms. Whitmer’s statement to a local journalist on Thursday that she would not run for president in 2028. Ms. Whitmer, who is barred by term limits from seeking re-election as governor this year, seemed to walk back her statement several hours later, leaving little clarity about whether she has really ruled out a quest for president in two years.

“There’s been so many people that have thought that she’s been doing the things she’s been doing, or the way she’s doing them, because she’s setting up for a run for president,” said State Representative Joey Andrews, a Democrat who praised her tenure and defended her motives for engaging with Mr. Trump as an effort to get what she could for the state of Michigan.

If a presidential run is off the table, Mr. Andrews said before the governor walked back her remarks, “I think it really does help kind of clarify what her intentions are.”

A Fast Rise

Ms. Whitmer was barely a year into her first term in 2020 when the Democratic Party picked her to give the response to Mr. Trump’s State of the Union.

The speech was Ms. Whitmer’s introduction to a national audience after a career spent mostly in the minority party of the Michigan Legislature. But she was truly put to the test a few weeks later, when Detroit emerged as one of America’s first Covid-19 hot spots.

Ms. Whitmer locked down her state and called out Mr. Trump for what she saw as a flawed pandemic response. The president fired back, mocking her as “the woman in Michigan” and “Gretchen ‘Half’ Whitmer.”

As variations of “the woman in Michigan” started turning up on T-shirts, Ms. Whitmer embraced her newfound national profile. She sat for interviews with major news outlets, went along with the nickname “Big Gretch” and drew praise for her often funny social media posts. She made Joseph R. Biden Jr.’s shortlist of potential running mates.

The growing attention also made her a target.

Shortly before Election Day in 2020, prosecutors announced charges against more than a dozen men accused in connection with a plot to kidnap her and possibly kill her.

Ms. Whitmer blamed Mr. Trump’s rhetoric for the plot, while Mr. Trump downplayed the threat. (The cases ended with a mix of convictions, acquittals and plea deals.)

Ms. Whitmer remained popular in Michigan, where she won re-election in 2022 by nearly 11 percentage points.

She also started making the moves that ambitious politicians make when they see a future president in the mirror. She stumped for candidates in other states. She wrote a book. And she used her leverage in the State Capitol to push through a smorgasbord of liberal legislation on guns, L.G.B.T.Q. rights, abortion access and labor issues.

Some Democrats, worried about Mr. Biden’s sagging poll numbers and visible frailty, talked about Ms. Whitmer as a tantalizing alternative to take on Mr. Trump. But like other A-list Democrats, she declined to mount a primary challenge to the sitting president.

A Sharp Pivot

Matt Hall, the Republican speaker of the Michigan House of Representatives, did not see it coming.

Soon after Mr. Trump won Michigan and was elected to a second term in 2024, Ms. Whitmer, who had sparred with Mr. Trump the first time around, signaled that she now wanted to work with him. Before long, Ms. Whitmer was visiting the White House — awkwardly shielding her face from a photographer on one trip — and appearing onstage with Mr. Trump to announce the fighter jets for Selfridge Air National Guard Base near Detroit.

“It’s been so helpful that she’s done that pivot,” said Mr. Hall, who joined Ms. Whitmer on a visit to the White House. “And we’ve been able to work together, and we’ve been able to achieve so much more for Michigan.”

Mr. Hall, a longtime Trump supporter, described the president and the governor as having “a great rapport.” Ms. Whitmer, he said, had shared points of disagreement with Mr. Trump, but also sought out common ground. Mr. Trump was “very complimentary of her,” Mr. Hall said.

Ms. Whitmer’s office did not make her available for an interview on Thursday. In a speech this week, she said that “our collaboration on Selfridge is proof we can disagree — vehemently at times — and still find common ground if we try.”

Ms. Whitmer’s approach has been noticeably different than other Democratic governors with national profiles, like JB Pritzker of Illinois and Gavin Newsom of California, who have warned of creeping authoritarianism and criticized the president in starkly personal terms. Those states, which are more solidly Democratic than Michigan, have also been singled out by the Trump administration for immigration enforcement campaigns and attempts to deploy federal troops.

Whether presidential primary voters in two years will reward combativeness or cooperation remains an open question. But in interviews this week on Michigan’s Mackinac Island, where politicians and business leaders gathered for an annual conference that was a bit like summer camp with sport coats, some of Ms. Whitmer’s friends and allies seemed uncertain what to think about the governor’s strategy.

“I think I might have chosen a different tack myself,” said State Senator Winnie Brinks, the leader of her chamber’s Democratic majority. “But I am not somebody who has walked in her shoes for the last eight years as governor, so I trust her judgment in terms of what she is doing and what’s best for the state.”

State Representative Carrie Rheingans, a Democrat, said she understood Ms. Whitmer’s motivations for trying to work with the president and appreciated the successes she found doing so. Still, Ms. Rheingans said that “I really miss the Big Gretch from the pandemic” and that “I would like to see more pushing back on some things.”

“I guess you’ve got to pick your battles,” Ms. Rheingans said, “and I might be more on the side of picking-all-the-battles than she is.”

Other Democrats said Ms. Whitmer’s approach made sense, especially in a politically mixed state. Senator Gary Peters, a Democrat who is not seeking re-election to Congress, described the intraparty critiques of Ms. Whitmer as unfair and reflective of a political environment in which members of both parties penalize cooperation.

“They reward people who are yelling the loudest, as opposed to, are getting the most done,” Mr. Peters said.

For years now, Republicans and Democrats in Michigan have mused about whether Ms. Whitmer might land on a national ticket, and about how any decision she made as governor might help or hurt those odds. All week on Mackinac Island, the carless tourist spot in Lake Huron with horse-drawn taxis and a startling rate of fudge shops per capita, her prospects were again a favorite topic of banter.

But Ms. Whitmer, who has seven months left as governor, seemed to put a stop to the speculation on Thursday morning in an interview with WJBK-TV of Detroit on the porch of the island’s Grand Hotel.

“There will be a robust group of people running for president,” Ms. Whitmer told the station’s reporter. “I will not be one of them in 2028. I can tell you that.”

Ms. Whitmer is a careful speaker with plenty of experience dodging questions about exactly that topic. Her comment on Thursday seemed unambiguous. But it surprised many at the conference, including legislators who thought she of course wanted to run for president, or to at least keep the door open. Some openly doubted that she meant what she had said.

“She’s blowing smoke,” said State Senator Jim Runestad, the chairman of the Michigan Republican Party, in an interview a few hours after her statement.

Indeed, by day’s end, the presidential door seemed to have cracked open again. Back at the Grand Hotel, after Ms. Whitmer delivered a valedictory speech about her tenure to a friendly crowd, a moderator asked about the newsy morning.

She noted that she had been asked lots of questions that morning. She said it had been the reporter, not her, who had brought up 2028. And then, without offering specifics, she said, “Never say never.”