Democrat congresswoman Hayley Stevens has stunned her party, two days before the midterm elections, by endorsing a Republican candidate in a seat critical to their chances of gaining control of the Senate.

Stevens previously called Mike Rogers – the Republican she now endorses – a “rubber stamp for Donald Trump’s dangerous agenda”. After her announcement she was immediately rounded on by her party and former staff, who resigned in protest.

Senate minority leader Chuck Schumer called the move a “despicable betrayal”.

Who is Hayley Stevens?

Democrat Michigan representative Haley Stevens, 43, began her political career working for Hillary Clinton’s presidential campaign in 2008. She was elected to Congress in 2018 and ran for the Democratic Senate primary this year, narrowly losing to the progressive Oxford graduate Abdul El-Sayed.

Michigan is considered a swing state, and holding this seat is vital for the Democrats’ hope to win the Senate. El-Sayed has become the focus of intense Republican attacks, that have tried to portray his vocal criticisms of Israel as antisemitism, and to link him to radical militants.

Ostensibly, Stevens’ decision to disendorse El-Sayed was over an election ad produced by a third party, which linked the cost of groceries to the US support for Israel “killing Palestinians”. Stevens said the ad was “antisemitic” and said it “dramatised” an argument that El-Sayed himself had made. She demanded he explicitly condemn it.

In response, El-Sayed said “that ad was not made by me, and I do not agree with the contents of that ad”, and said he wanted to talk about issues “relevant to the voters” of Michigan rather than “this stuff that [the media] push for clicks”.

He accused Stevens of “relitigating a primary that ended three months ago”, and reportedly asked her not to attend any more of his campaign events because she was an unwelcome distraction in a pivotal election.

In a press interview, Stevens said she became disillusioned with El-Sayed at a campaign debate three weeks ago, when El-Sayed was asked whether Israel or Iran was a bigger threat to the US, and replied that it was a “ridiculous hypothetical” question and they “both have proven dangerous in their own way, one at risk of attacking us, one getting us into wars we have no business fighting”.

Then on Sunday Stevens appeared at a Republican campaign stop for Rogers, stood beside him and announced “I am endorsing Mike Rogers for the United States Senate”.

She complained that El-Sayed had “made it clear that I was not welcome in his campaign” and said “at some point you gotta look at who’s standing [up for your] country”.

“We can’t stand with hate,” she said. “This was a personal and private decision… I’m not trying to harm anyone [and] I still love the [Democratic] party.”

In a video on social media she insisted she was “still a very proud Democrat”.

In an interview on CNN, Stevens struggled to explain what had changed her mind to endorse Rogers, but said it happened after being “alone with my thoughts” on Saturday night and it was “a weight off my shoulders”.

Stevens’ move prompted howls of outrage across her party and from close colleagues.

Her congressional chief of staff immediately resigned, issuing a statement on behalf of her entire office saying they were “shocked and heartbroken” by the endorsement. Her former communications director for her Senate campaign said her “ridiculous and pathetic” decision had “betrayed all those values” she had campaigned for.

Stevens told CNN she was “running down my office, it’s all been packed up” after her staff resigned.

Several Democrats said Stevens had previously assured them she would back al-Sayed.

In a passionate message that quoted Dr Martin Luther King. Massachusetts congresswoman Ayanna Pressley said she had spoken to Stevens the day before about “the importance of unity in this moment”.

“[I] reminded her who has been suffering under this hostile fascist administration, and the co-conspirators like Mike Rogers, who have been complicit in harm to everyone who calls this country home, including, and especially black people, because we know when everybody else catches a cold, black people catch pneumonia,” she said.

“She said she understood the assignment, did not want to be a distraction. and planned to vote for Abdul.”

New York Democrat nominee for Congress Brad Lander accused Stevens of having “primary-loser-sour-grapes”.

Schumer, who had supported Stevens in the primary, said Senate Democrats were “united in our support for Abdul El-Sayed”.

 El Sayed said “at the end of the day, I actually don’t think about Haley Stevens.”

In August, Trump called Stevens a “radical left Socialist” (in the same post, he called El-Sayed a “Communist”).

On Sunday, on social media he said she had shown “great and almost unprecedented loyalty to the great people of Michigan… it’s a thing called bravery”.

At a rally in Iowa Trump claimed Stevens had lost the primary because it was rigged, and said “I’d love her to join the Republican Party actually, I think that could happen maybe”.

He also called El-Sayed a “jihadist lunatic… can you imagine, we’ll have to put him through metal detectors in order to seat [him in the Senate]”.

Republican House Speaker Mike Johnson said Stevens “did a heroic and important thing for the country”.

What Stevens has said about Rogers

Angry Democrats – and the media – were quick to revisit some of the previous statements that Stevens had made about the man she has now endorsed.

They included saying Rogers’ “record on LGBTQ+ rights is repulsive”, that he “can’t hide his terrible record on abortion rights”, that he “would be another vote against our environment” and was “an out-of-touch, out-of-state millionaire who is unfit to represent Michigan”.

The latest New York Times poll has El-Sayed on 53% and Roberts on 42% among a welter of Senate races that appear to be moving strongly in the Democrats’ favour.