Multiple news outlets now confirm that Rep. Bart Stupak will announce his retirement today at a press conference scheduled for 12:30 eastern time.

Sources tell Chris Cillizza that Stupak was “burned out from the long fight over health care,” and Dave Weigel calls it a “major coup” for the tea party movement, or more specifically, the Tea Party Express, which just launched an ad campaign against the congressman.

Assuming all of these reports are accurate, the seat would represent a prime pickup opportunity for Republicans. In 2008, Michigan’s 1st Congressional district voted for Obama over McCain by a narrow 2-point margin, while Stupak won with 65 percent of the vote. Because of his pushing for stronger abortion language during the health care debate, Stupak actually drew a primary challenger from the left. While Stupak won the district with endorsements from pro-life groups, his Democratic challenger, Connie Saltonstall, boasts on her campaign site that she’s endorsed by NOW, NARAL and Planned Parenthood. She’s a former county commissioner.

On the Republican side, Dan Benishek, a local surgeon, had been preparing to challenge Stupak in the general.

UPDATE: Cook Political Report has moved the race from “Solid Democratic” to “toss up”:

Without Stupak on the ballot, however, expect a free-for-all. This geographically huge district is as politically mixed as they come. In fact, no district voted more narrowly for President Obama in 2008. Here, deep roots in the community matter more than party affiliation. When Stupak (who is from Menominee on the Upper Peninsula) first won this seat in 1992, 54 percent of 1st CD residents lived on the Upper Peninsula. Due to population loss and redistricting, 53 percent of residents now live south of the Mackinac Bridge. Prior to Stupak’s election, Republicans had held this seat since 1966.

To keep this seat in the current political environment, Democrats will need to field a culturally conservative candidate with impeccable northern Michigan credentials. Look for plenty more Republicans besides the only current announced candidate, surgeon Dan Benishek, to take a look at the race. This seat moves from the Solid Democratic column to the Toss Up column.