DETROIT — There’s a reason it’s a swing state.

Michigan voters threw a wrench in expectations that Dr. Abdul El-Sayed would easily coast to victory over Rep. Haley Stevens in the closely watched Democratic Senate primary.

The race had been seen by El-Sayed’s backers as a battle for “the soul of the Democratic Party,” and the far-left’s attempt to prove that their candidates are just as electable, if not more, than centrist Dems.

But despite El-Sayed’s frequent double-digit leads in most polling, he wrapped up his watch party speech with a nearly two-percentage point lead that was shrinking.

“I wish I could tell you that I was declaring victory right about now. Turns out it takes a long time to count votes in Michigan,” he said. “Right now we are on track to outvote the historical numbers that we should expect.”

Ironically, El-Sayed declared in his speech that “We are not a purple state; we are a state in need of a movement to take our politics back.” He tore into narratives about voters caring about ideology and whether someone was too far to the left.

El-Sayed also pointed out how nearly $80 million was spent on the primary and that he had been outspent 12 to 1.

“Right now we are on track to outvote the historical numbers that we should expect,” he added, casting himself as the underdog in the race.

El-Sayed also made an overture to Democrats who didn’t back him in the bruising primary.

“There is so much more that unites us. However much we might disagree with our Democratic opponent, there is so much more that unites us than divides us,” he said.

Republican Mike Rogers had told The Post that he expected the winner of the Democratic primary to have coalition struggles, something he blamed on his 2024 Senate loss.

Stevens addressed her watch party in a triumphant mood.

“I know it’s been an exciting night. I know it’s been a long night because that’s the Michigan way,” she told her followers. “We knew that this was going to be a close race, and that’s exactly what we’ve got.

“But friends, I am feeling good about this race.”

Tuesday night was full of mixed results in the battle between the far-left and mainstream elements of the Democratic Party.

In Missouri, Cori Bush got walloped in her comeback bid against incumbent Rep. Wesley Bell (D-Mo.), wrecking narratives about pro-Israel Democrats being electoral toast.

Elsewhere in Michigan, “Squad” Rep. Rashida Tlaib (D-Mich.) easily clinched the nod, but in Michigan’s 1st Congressional District, Callie Barr defeated Democratic socialist candidate Kyle Blomquist.

But in Michigan’s 7th Congressional District, Bernie Sanders-backed William Lawrence won in what is one of the most competitive districts in the country.

Then there was Michigan’s 14th District, where Democratic Socialists of America-backed Donavan McKinney was in a too-close-to-call race against incumbent Rep. Shri Thanedar (D-Mich.)