Maine Republican Senator Olympia Snowe has announced her retirement.

A moderate Republican, who has often voted with Democrats in the Senate cited the extreme partisanship of recent years as her reasoning.

In a statement Snowe said, “Unfortunately, I do not realistically expect the partisanship of recent years in the Senate to change over the short term. So at this stage of my tenure in public service, I have concluded that I am not prepared to commit myself to an additional six years in the Senate, which is what a fourth term would entail.”

Notice of her retirement could be a “major setback for the GOP’s efforts to regain a majority in the Senate.” With Maine being a blue state, Snowe was considered as a moderate, to be the GOP’s only hope to hold the seat.

Among the names mentioned as possible replacements on the ballot for the GOP: 2002 gubernatorial candidates Peter Cianchette, 2010 gubernatorial candidate Steve Abbott, state Treasurer Bruce Poliquin, state Attorney General Bill Schneider, and Jock McKernan, Snowe’s husband and the state’s former governor. Businessman Scott D’Amboise was already challenging Snowe in a primary.

On the Democratic side, Reps. Chellie Pingree (D) and Mike Michaud (D) could run, as well as former congressman Tom Allen (D), who unsuccessfully challenged Sen. Susan Collins (R-Maine) in 2008.

The filing deadline is fast approaching: March 15.

Progressives are already crowing that Snowe is retiring and it can indeed be a win/win for Democrats, but let’s celebrate when we win her seat. Snowe has always been an ally on women’s issues, and with the surge in the war on women, we very much need a pro-choice, pro-women’s issues vote to replace her.

On the flip-side Democrats are losing their most moderate member, Senator Ben Nelson of Nebraska. Former Senator Bob Kerrey is said to be reconsidering running for Nelson’s seat.