From the time she burst onto the political scene in 2020, Marjorie Taylor Greene represented a particularly extreme version of MAGA.
She had a history of promoting conspiracy theories, positing that Democratic politicians were part of a satanic child sex-trafficking ring and that a space laser connected to the Rothschild family started wildfires in California.
And as the congresswoman for a conservative stretch of northwest Georgia, she was one of the House of Representatives' loudest voices for America First: pushing to overturn Donald Trump's election loss to Joe Biden, championing the deportation of undocumented immigrants and calling for the end of U.S. military aid to Ukraine. Along the way, she became one of Mr. Trump's closest legislative allies.
But in the space of just a few weeks this fall, she broke with the President on several fronts, criticizing his failure to extend Obamacare tax credits that keep insurance premiums down, chiding him for focusing on foreign affairs over lowering the cost of living at home, and joining a successful effort to force the release of files on child sex trafficker Jeffrey Epstein, initially over Mr. Trump's objections.
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Mr. Trump, in return, labelled her "Marjorie 'Traitor' Greene" and solicited a primary challenger to her next year. Ms. Greene responded by announcing her resignation.
The whirlwind has left observers wondering how one of the country's tightest political alliances imploded so quickly, and whether it represents a broader split within Mr. Trump's movement or simply the clash of two titanic personalities.
Ms. Greene herself has explained the falling out partly as a disagreement over policy and partly about Mr. Trump's autocratic style of governance.
In a video announcing her surprise resignation, she chided her fellow Republicans for not working to "protect Americans from outrageous, overpriced and unaffordable health insurance" and declared that "America First should mean American First and only Americans First."
On X a few days later, she complained that Congress has been "totally sidelined" by Speaker Mike Johnson "under full obedience" to Mr. Trump's White House, which prefers to operate by executive order.
Former Trump loyalist Marjorie Taylor Greene resigning from Congress
Nathan Price, a political scientist at the University of North Georgia, said he believes that Ms. Greene is motivated at least in part by sincere ideological disagreements with Mr. Trump. Earlier this year, he pointed out, she criticized Mr. Trump's decision to get involved in Israel's war with Iran and has talked about how her own children are struggling to afford health care premiums.
"There is some sincerity in her belief that she has not changed substantively from her America First, populist brand of politics, while Trump has," he said. "There seemed to be genuine frustration that the administration was focused on foreign-policy issues and not those issues closest to home."
But both are also "huge personalities" and have a history of clashing with members of their own parties, Prof. Price said, pointing to Ms. Greene getting kicked out of the right-wing House Freedom Caucus two years ago.
Ricky Hess, a Republican organizer in Ms. Greene's congressional district, suggested that the split between the congresswoman and the President was not representative of party divisions on the ground. In his discussions with Republican voters, he said, people support both Ms. Greene and Mr. Trump, and don't blame the President for their bread-and-butter economic problems.
"Most voters tell us the same thing, they like both of them and hope they patch things up. People here see them as fighters on the same team," said Mr. Hess, chairman of the Paulding County Republican Party. "The frustration isn't aimed at the President. It's the economy, the cost of living, and the feeling that Washington isn't listening."
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Indeed, Ms. Greene's criticism of Mr. Trump on affordability issues, such as health care, is closer to the views of swing voters than of the MAGA base.
Polling by Politico suggests that, of Mr. Trump's voters in 2024, 55 per cent identify as MAGA and 38 per cent do not. Of the MAGA voters, 85 per cent trust Republicans to bring down health care costs, compared with just 55 per cent of non-MAGA Trump voters.
Still, some of the criticism Ms. Greene is levelling at Mr. Trump is broadly representative of voters' frustrations with him. A Reuters poll this month found that his approval had fallen to 38 per cent, the lowest of his second term so far, with just 26 per cent of respondents approving of his handling of everyday expenses and 20 per cent of his handling of the Epstein files.
Ms. Greene has even made some tentative bids for mainstream acceptance, including an interview last month on The View, the long-running ABC daytime talk show, in which she shied away from her embrace of conspiracy theories.
When asked about QAnon, she replied: "I went over that a long time ago" and was "a victim, just like you were, of media lies and stuff you read on social media." On the space laser, she said: "Not even true. Yeah, that's been rebuffed."
Trump breaks with Marjorie Taylor Greene as feud between former allies escalates
Previous complaints that Mr. Trump was straying from his base, meanwhile, have tended to quickly fizzle.
This past summer, for instance, the late MAGA influencer Charlie Kirk initially questioned both U.S. intervention in the Israel-Iran war and the Trump administration's refusal to release the Epstein files. But he ultimately accepted both decisions.
And Ms. Greene joins a long list of top Trump allies - from Jeff Sessions to Steve Bannon to Elon Musk - who have experienced a falling-out with him.
Prof. Price offered the anecdote of one of his former students, who worked for the state Republican Party, to illustrate the President's hold. Whenever the former student would canvass for a Republican candidate, voters would have no interest in hearing about the politician's positions on any issues - they would just want to know whether the candidate had Mr. Trump's support.
"It's extremely difficult for me to imagine a candidate winning a primary in one of these heavily Republican districts if they are going to try to run against President Trump," he said.