Peters a Bloomfield Township Democrat, made his announcement Wednesday in Rochester, saying that there'll be a clear contrast between him and whoever the eventual Republican candidate may be.
One Republican who has enough cash to get into a statewide battle over Michigan's open Senate seat is U.S. Rep. Mike Rogers, a Howell Republican.
But is Rogers ready to give up his chairmanship of the House Intelligence Committee and the seat in Congress he's had for a dozen years to risk a loss in what promises to be a spirited election battle for the Senate seat being vacated by Democrat Carl Levin?
Peters has proven to be an aggressive campaigner and able to raise campaign cash. Two of his three elections to the U.S. House have been pitched battles.
So far, Rogers isn't saying.
But if not Rogers, then who?
Oakland County Sheriff Mike Bouchard, a U.S. Senate candidate in 2006, losing to Democratic Sen. Debbie Stabenow 57-41 percent, says he's already taken one for the GOP team and isn't interested.
Might Midland Republican U.S. Rep. Dave Camp be interested? He's chairman of the House Ways and Means Committee and, like Rogers, he'd have to give up a powerful committee and his seat to take on Peters.
After those two, the list of Republicans who might be intersted AND can muster the cash for a statewide campaign gets pretty slim.
But it's a safe bet the GOP won't let Peters capture the seat without a challenge.
Both the Michigan Republican Party and the National Republican Senatorial Committee have wasted no time attacking Peters for his support of Obamacare, indicating that some Republican candidate will emerge as a challenger at some point.