GRAND RAPIDS, Mich. (AP) — Outgoing Michigan Sen. Gary Peters is endorsing U.S. Rep. Haley Stevens as his successor, adding to a growing effort by the Democratic establishment to help her defeat progressive favorite Abdul El-Sayed in next month’s primary.Peters, who is retiring after 12 years in the Senate, said Stevens “will be ready on day one to fight for Michigan.” The endorsement, which was announced Monday, marks a reversal for Peters, who told The Associated Press in late May that he intended to stay neutral in the race. But since then, Democratic leaders have increasingly rallied behind Stevens as the Aug. 4 primary approaches and concerns grow that El-Sayed is too far left to succeed in November. Holding the Michigan seat is viewed as critical to Democrats’ hopes of reclaiming the Senate majority.Stevens, a four-term House member, has campaigned as a more moderate Democrat focused on manufacturing issues in the critical battleground state. El-Sayed, who has never held elected office, is running on a more progressive platform that includes Medicare for All and campaign finance reform. He’s also been outspoken about the war in Gaza, which has been a fault line within the party. Concerns about Michigan have only intensified after Democrats’ attempt to flip a Senate seat in Maine was thrown into turmoil when nominee Graham Platner withdrew from the race following a sexual assault allegation last week. Democrats there must now choose a new nominee to face Republican Sen. Susan Collins.