Harper, an actor on “The Good Doctor,” has never run for office before. He is expected to run to the left of Slotkin, a moderate, three-term Democratic House member who represents a swing district. His allies believe Harper, who is African American, will be able to build a coalition that includes progressive and Black voters. They also point to his history serving on President Barack Obama’s cancer panel and his ties to well-heeled potential donors in Hollywood.

“I think Hill getting in the race would be a really good thing for Michigan Democrats,” said Washtenaw County Sheriff Jerry Clayton. “In my experience, coronations tend to hurt the party, while robust and competitive primaries with a healthy and respectful debate over the real issues tends to help.”

Some Democrats cautioned that Harper’s bid isn’t a sure thing until he announces he’s running. He had initially prepared for an April kickoff.

If Harper pulls the trigger, he will face an uphill climb. Slotkin had $2.3 million on hand at the end of March, according to campaign finance reports. And she is expected to win the support of much of the Democratic Party statewide and nationally. EMILY’s List, VoteVets, End Citizens United, Rep. Haley Stevens and the Michigan Building Trades Council have endorsed her.

Many of Slotkin’s would-be Democratic competitors have already opted against a Senate campaign, including Lt. Gov. Garlin Gilchrist, Michigan Secretary of State Jocelyn Benson and state Sen. Mallory McMorrow. Retiring Sen. Debbie Stabenow (D-Mich.), who Slotkin is running to replace, helped narrow the field.

Harper will also have to take on several other Democrats who have jumped into the Senate race, including Michigan State Board of Education President Pamela Pugh, former state Rep. Leslie Love, businessperson Nasser Beydoun and attorney Zack Burns.

On the GOP side, State Board of Education member Nikki Snyder, former Berrien County Commissioner Ezra Scott, businessperson Michael Hoover and attorney Alexandria Taylor are among those vying for the job.