Representative Haley Stevens, Democrat of Michigan, on Sunday withdrew her support for Dr. Abdul El-Sayed, the Democratic nominee for Senate in the state and her former primary rival, and endorsed his Republican opponent, a stunning last-minute turn in a race that is critical to the battle for Senate control.
“Our Democratic nominee for U.S. Senate, Abdul, said that I was no longer welcome in his campaign and that I should stay away,” Ms. Stevens said in a video on social media. “And he’s right. And that’s why I am voting for Mike Rogers for United States Senate.”
The extraordinary development reflected both the bitter disagreements over Israel and the personal animosity between the two prominent Michigan Democrats.
Ms. Stevens, a moderate and a strong supporter of Israel, often clashed with Dr. El-Sayed, an outspoken progressive critic of the country, during their contentious primary race. After he narrowly beat her in August, she immediately endorsed him and they seemed to reach a quiet truce. Then, this month, she began to criticize him in news interviews, and in recent days, they traded public barbs over his stance on Israel. But she continued to cautiously commit to supporting Dr. El-Sayed and the full Democratic ticket.
Ms. Stevens’s endorsement video went online while she appeared on Sunday morning with Mr. Rogers at a Black church in Detroit. In the video, she said she “does not stand with Dr. Abdul’s campaign,” nor with Hasan Piker, a provocative left-wing streamer with whom Dr. El-Sayed campaigned in the primary and from whom he later distanced himself.
Ms. Stevens cast the Senate race — which has also included waves of Republican attacks on Dr. El-Sayed’s Muslim faith and background — as a referendum on hate in politics. She added that she was “still a very proud Democrat.”
Miles away, Dr. El-Sayed was at a church service with other Democratic leaders, an event that had been intended to display party unity. On Saturday, he had publicly urged Ms. Stevens to stay away from that gathering, deepening the growing tension between the two Democrats.
After the news of Ms. Stevens’s endorsement of Mr. Rogers, Dr. El-Sayed sought to downplay its significance.
“None of this matters,” he told reporters.
Ms. Stevens’s move shocked other Democrats and upended her congressional office, with several top officials announcing their resignations. Many Democrats condemned the effort to undermine Dr. El-Sayed so close to an important election for the party.
Senator Chuck Schumer of New York, the Democratic minority leader, called the move a “despicable betrayal.” The chair of the Democratic National Committee’s Black Caucus, Virgie Rollins, accused Ms. Stevens of “using Black Michiganders for a political stunt” and called her a “sellout.” And the chair of the Michigan Democratic Party, Curtis Hertel, accused Ms. Stevens of having “abandoned everything she claims to care about.”
Ms. Stevens’s chief of staff, Justin German, announced Sunday that he and “many members of her team” had resigned over the decision. “This election is too important to sow division or stand on the sidelines,” he wrote in a statement, adding that staff members had been “heartbroken” by Ms. Stevens’s decision. Logan Basch, Ms. Stevens’s director of communications, also resigned on Sunday, according to an auto-reply email.
Representative Jamie Raskin, a Maryland Democrat, said in an interview that he had been “blindsided” by Ms. Stevens’s decision, and that she had told him in a phone call around 10 p.m. on Saturday night that she was still behind Dr. El-Sayed.
Mr. Raskin recalled in an interview that he had pressed Ms. Stevens. “I just want to be very clear about that: You’re supporting the whole ticket, including Abdul?” he recalled asking her. “And she said yes.”
Addressing reporters after the service, Ms. Stevens said that she “woke up this morning and I decided to go to church and I am here with the person that I am voting for, for United States Senate. And that is Mike Rogers.”
President Trump, who has repeatedly made anti-Muslim attacks against Dr. El-Sayed, said on Truth Social that Ms. Stevens had shown “bravery” and “almost unprecedented loyalty to the Great People of Michigan.”
Ms. Stevens’s announcement capped off a roller-coaster week of public back and forth between the two Democrats.
Last week, Ms. Stevens demanded that Dr. El-Sayed denounce an ad from an outside group that she has argued amounts to “fear-mongering about Israel.” But on Thursday, Ms. Stevens said that she planned to campaign with Dr. El-Sayed this weekend.
Those plans, however, were upended when she issued a statement on Friday morning demanding an apology for comments Dr. El-Sayed had made about Israel.
Dr. El-Sayed pushed back, saying she was no longer welcome.
“I don’t want any distractions,” he told reporters on Saturday. He added, “It seems as though other folks are more interested in making this race about things that it’s not about.”
On Sunday, Dr. El-Sayed attended the service without Ms. Stevens at Greater Emmanuel Institutional Church of God in Christ. Representative Debbie Dingell of Michigan and Senator Angela Alsobrooks of Maryland also attended, and Representative James E. Clyburn, Democrat of South Carolina, introduced Dr. El-Sayed at the event. A third former Senate primary candidate, Mallory McMorrow, was also there.
Ms. Stevens had strong support from Black voters in Detroit during the primary, and Dr. El-Sayed has worked to gain their support during the general election. Mr. Rogers has also campaigned heavily in Detroit.
Early this month, Ms. Stevens expressed confidence that Black voters would support Dr. El-Sayed over Mr. Rogers, telling CNN that Black voters “know that our Republican nominee, he’s certainly not going to lift a finger for Social Security and Medicare, and, you know, a host of issues that are on the ballot.”
On Wednesday, however, Ms. Stevens suggested in another CNN interview that Black voters were wavering on whether to support Dr. El-Sayed, an Egyptian American who has struggled to bridge tensions between Black and Arab American voters in the Detroit area.
“I’m hearing from Black voters, and I still want the Democratic Party to have these coalitions in it,” Ms. Stevens told CNN’s Kaitlan Collins. She called on Dr. El-Sayed to “make people who are in my coalition feel comfortable coming to the polls.”
Ms. Stevens and Mr. Rogers sat together in the second pew at Perfecting Church, a prominent Black church in Detroit, on Sunday morning. Mr. Rogers’s wife and Jason Turkish, Ms. Stevens’s fiancé, also attended. Mr. Turkish has endorsed Mr. Rogers.
Evan Gorelick and Shane Goldmacher contributed reporting.
