James Craig, a Republican, Enters Michigan Senate Race

James Craig, a former Detroit police chief, announced on Tuesday that he was running for the Senate seat in Michigan being vacated by Debbie Stabenow, a Democrat who is retiring after more than two decades in the position.

Mr. Craig, 67, ran for governor of Michigan last year and was leading early Republican primary polls until he was disqualified because of forged signatures on his nominating petition.

He is likely to promote his background in law enforcement as he campaigns on some of the conservative priorities that have helped propel former President Donald J. Trump.

But national Republicans have privately expressed concerns about Mr. Craig’s candidacy, worrying that personal issues, including multiple bankruptcies and divorces, could prove detrimental to his campaign.

The campaign arm for Senate Republicans, the National Republican Senatorial Campaign Committee, has recruited former Representative Mike Rogers, 60, to run for the seat.

The Democratic Party’s best-known candidate so far is Representative Elissa Slotkin, who was elected to Congress in the blue wave of 2018 and has won re-election twice in a swing district. Her primary opponents include Hill Harper, an actor; Nasser Beydoun, a businessman; and Pamela Pugh, the president of the State Board of Education.