Rep. Gary Peters (D-Mich.) continued to solidify the establishment support behind his Senate candidacy Thursday, adding official endorsements from Sens. Carl Levin and Debbie Stabenow.

"Like me, Gary has spent his whole life in Michigan. Gary’s parents, a public school teacher and nurse’s aide, instilled in him the importance of hard work, integrity, and the promise of the American Dream," wrote Levin, who is retiring, in an e-email to supporters. Added Stabenow in her own note: "I’ve known Gary for more than 20 years. He is a devoted husband and father who is raising his family in Oakland County, where his own family has been for generations."

The endorsements from Levin and Stabenow are not surprising. Peters has been the clear choice of the Democratic establishment since he entered the race. When Debbie Dingell opted against a Senate bid, it's became clear that Peters was set to cruise to the Democratic nomination.

The Republican race is much more fluid. The big question is whether Rep. Mike Rogers (R) will run. The chairman of the House Intelligence Committee also is on the unofficial list of names under consideration to be the next head of the FBI.

Rep. Justin Amash (R), a libertarian-leaning Republican who has clashed with House leadership, is another possibility.