U.S. Sen. Bernie Sanders, the independent Vermont senator who ran for president in 2016, will travel to Ann Arbor next week in an effort to fire up progressive voters for Gretchen Whitmer's gubernatorial campaign.

Sanders backed Democrat Abdul El-Sayed in the race for governor before the Aug. 7 primary and appeared at a rally for El-Sayed's campaign the weekend before that election. But the former Detroit health department director finished second of three candidates in the race, behind Whitmer and in front of retired Ann Arbor businessman Shri Thanedar.

While Sanders said Whitmer is the candidate who will help ensure every Michigander has clean drinking water and access to quality schools, his endorsement of the campaign presents some challenges, too.

Reforming campaign finance by getting political action committee dollars out is a key issue for Sanders as well as a transformation of health care into a single-payer, government-run system.

But Whitmer has accepted PAC money in her race for governor and has not supported a single-payer system for health care, saying it would be difficult to implement such a system on a state level.

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Still, Sanders said in a statement endorsing Whitmer: “Too often, Michigan’s working families have been left behind by the political elite. That’s why Gretchen will work to get big money out of politics, invest in infrastructure, and move towards universal pre-school."

Whitmer said she was thrilled with the endorsement from Sanders, who narrowly won Michigan's presidential primary in 2016 over Hillary Clinton, propelled by throngs of young progressive voters who stood in line for hours and crammed auditoriums across the state for a chance to see him.

He'll rally with Whitmer and other Democratic candidates and elected officials at 7 p.m. Oct. 19 at the University of Michigan's Rackham Auditorium in Ann Arbor. The event is free and open to the public.

Contact Kathleen Gray: 313-223-4430, kgray99@freepress.com or on Twitter @michpoligal