DETROIT (AP) — Michigan Democrat Abdul El-Sayed’s former opponent in the U.S. Senate primary, Haley Stevens, stunned party officials Sunday by endorsing Republican Mike Rogers after Democratic tensions boiled over days before the election that could determine the balance of power on Capitol Hill.

Stevens endorsed Rogers after attending a Detroit church service with him. The remarkable show of support for President Donald Trump’s backed candidate in the tightly contested race comes after she was uninvited to a joint event the same day with El-Sayed, who defeated the congresswoman by a slim margin in the August primary.

“Our Democratic nominee for Senate said I was no longer welcome in his campaign and that I should stay away,” Stevens said video announcing the endorsement. “And he’s right. And that’s why I am endorsing Mike Rogers for the United States Senate today.”

While Stevens has been critical of El-Sayed’s comments surrounding Israel, she had recently reaffirmed she would vote for the former public health official who would be the country’s first Muslim senator if elected Tuesday. The fallout from her visit to Perfecting Church was swift, with her longtime chief of staff resigning and a number of staff members expected to follow soon, according to a person familiar with the developments who spoke on condition of anonymity to discuss internal matters.

As Stevens swayed alongside Rogers in the pews, El-Sayed was a few miles away at another church trying to present a united front with fellow Democrats. The Associated Press attended both services as the dramatic split-screen unfolded.

The latest and late-stage infighting comes as Democrats look to drive turnout among Black and Jewish voters in key strongholds. El-Sayed, a former Michigan public health official, is in a tight race with Rogers, an ex-congressman, for the seat held by Democrat Gary Peters, who is retiring. Keeping Michigan in Democratic hands is vital to the party’s effort to win a majority for the final two years of Trump’s second term.

“United we stand, divided we fall,” Rep. Debbie Dingell, D-Mich., had said hours earlier.