Divided Democrats face a moment of truth in Michigan Senate primary

Democratic socialists look like they're about to rack up a stunning new victory: Their candidate in Michigan's Senate Democratic primary has the momentum heading into Tuesday's primary.

Why it matters: A win by Abdul El-Sayed in the swing state would turbocharge the party's left flank and validate establishment fears about the party's direction.

The big picture: Establishment Democrats have watched in horror as democratic socialist candidates pull off one win after another in House primaries this year. The Michigan primary brings the ideological clash to its biggest stage yet.

• El-Sayed, who's backed by Sen. Bernie Sanders and Rep. Alexandria Ocasio-Cortez, is taking on an establishment favorite in a race that's become a proxy fight between the party's far-left and center-left wings.
• Democratic leaders have gone all-in for Michigan Rep. Haley Stevens because they think she can win moderate voters — and El-Sayed can't.
• But El-Sayed has vaulted to a hefty lead in the final stretch of the campaign. One survey this week had him up 15 points. Other polls have shown him with smaller but still substantial leads.
• The political stakes don't get much higher. If Democrats lose Michigan on Nov. 3, they almost certainly aren't winning the Senate.

State of play: Together with Zohran Mamdani's victory in the New York City mayor's race, democratic socialists have proven they're not on the periphery of the party anymore — the center of gravity has shifted unmistakably in their direction.

• A CNN poll out Thursday showed about a third of Democratic voters identify as democratic socialists — and they're the most motivated to turn out.
• But winning House primaries is one thing. Winning a statewide Senate primary in one of the nation's premier battlegrounds is another.

Driving the news: El-Sayed has gained ground as the campaign progressed.

• Stevens had a sizable lead early on, with El-Sayed in second and state senator Mallory McMorrow trailing. But El-Sayed moved up over the past two months, and in the weeks since McMorrow dropped out in early July, established himself as the frontrunner in polls.
• Stevens is the consensus choice of the Democratic establishment. Senate Majority Leader Chuck Schumer lined up behind her early. Michigan Gov. Gretchen Whitmer came aboard late, with an endorsement last week.
• The primary is also a monumental moment for AIPAC. The pro-Israel organization and affiliated groups have poured roughly $30 million into boosting Stevens — the most it's ever spent in a single race, per the AP.
• Israel is a central dividing line in the race: Stevens has described herself as a "proud pro-Israel Democrat." El-Sayed has accused the country of committing genocide in Gaza.

The intrigue: The bigger question for Democrats is whether the party is undergoing the kind of makeover Republicans experienced a decade ago with Donald Trump — or if the democratic socialist surge is confined to the bluest enclaves.

• No primary this year will offer a clearer answer than Michigan's.
• Democratic socialists argue they're filling a vacuum. Even as establishment Democrats say El-Sayed can't win, they've struggled to articulate their own vision beyond "Trump is bad" and "stuff is too expensive."

The other side: Republicans dejected by President Trump's record low approval rating and unpopular war are suddenly reveling in the opposition's leftward lunge.

• Trump has adopted a campaign strategy that boils down to: "You may not like me, but do you really want those crazy communists instead?"
• El-Sayed doesn't identify as a democratic socialist, but DSA organizers are going all out to help him. Sanders (I-Vt.) and Ocasio-Cortez (D-N.Y.) have both campaigned for him.
• Trump undoubtedly would cast the epidemiologist and former Rhodes scholar as another Democratic "communist."

What we're watching: An El-Sayed win would only be step one for the democratic socialist cause. To truly show the far-left wing can compete in the most competitive terrain, he'd need to win in November against Rep. Mike Rogers, the presumptive Republican nominee.