Democratic Rep. Haley Stevens jolted Michigan’s closely watched Senate contest just days before the election by endorsing Republican nominee Mike Rogers. The surprise move disrupted growing Democratic confidence in nominee Abdul El-Sayed and handed Rogers fresh hope in a race that could determine control of the Senate.

The endorsement followed several days of public attacks and private maneuvering. Stevens had spent months criticizing Rogers and recently assured prominent Democrats that she still supported El-Sayed, despite the strained relationship between the former primary rivals.

Rep. Jamie Raskin of Maryland told The New York Times that he spoke with Stevens around 10 p.m. Saturday. According to Raskin, Stevens insisted during the call that she remained behind El-Sayed.

Stevens also recently told former Speaker Nancy Pelosi that she intended to attend Sunday church services with El-Sayed, according to a source familiar with their private conversation. That appearance was supposed to offer Democrats a long elusive display of unity.

Meanwhile, Rogers’ campaign was arranging a church invitation of its own. His campaign invited Stevens on Saturday night to attend services with the Republican nominee the following day, according to another source familiar with the process.

By Sunday morning, Stevens had called Rogers to accept, he said. They embraced before the service, attended church together and then appeared at what looked like an impromptu joint press conference.

“I did endorse the Democratic nominee, and he chose to close his campaign by saying I wasn’t welcome,” Stevens said. She then made her stunning choice explicit: “My vote for Senate is going to be with Mike Rogers.”

Stevens added, “And I will tell you why: because we have to stand with the country.” Whether that declaration can meaningfully change the contest, however, remains uncertain with so little time left before voters make their decision.

A New York Times/Siena survey released Sunday placed El-Sayed ahead of Rogers by 11 points, 53% to 42%. The poll was conducted before Stevens delivered the endorsement, which developed rapidly and caught Democrats by surprise.

Stevens herself questioned whether the announcement could shift many votes. “I’m not trying to sway any election,” she said outside the church, describing the endorsement as her personal decision rather than an effort to reshape the entire result.

The congresswoman also said she believes Sen. Chuck Schumer of New York “is going to become the majority leader” and called herself a “proud Democrat.” Rogers nevertheless seized on the moment, describing El-Sayed as “angry and divisive” during an interview with NewsNation.

“We feel great where we are today,” Rogers said about the race. Some Michigan voters, however, were openly skeptical that Stevens could substantially alter the outcome at such a late stage.

Megan Slattery, a 55 year old yoga and pilates instructor from Hazel Park, told MS NOW after an El-Sayed rally that she did not think the endorsement would “make a difference at this point.” She called Stevens “disgusting” and “a joke.”

Douglas Doggett, a 40 year old entrepreneur who supported Stevens in the primary, called her endorsement “very disappointing,” “unnecessary” and “a real slap on the wrist.” He said Democrats could not afford such turmoil with only two days remaining before the election.

The fallout quickly reached Stevens’ own congressional office. Minutes after the endorsement, longtime chief of staff Justin German announced that he and “many members of our team have resigned,” adding, “We are shocked and heartbroken by Congresswoman Stevens’ decision to support Mike Rogers.”

Stevens had initially planned to appear Sunday with El-Sayed and Rep. Jim Clyburn of South Carolina at a Detroit church for a Get Out the Vote event. But the plan began unraveling Friday as Stevens criticized an advertisement connecting high grocery prices with United States aid for Israel.

El-Sayed accused Stevens of being “intent on litigating a primary that ended three months ago.” His campaign later asked her to avoid future campaign events, and when questioned Sunday about her endorsement, El-Sayed replied, “At the end of the day, I actually don’t think about Haley Stevens.”