Hours after Maine Sen. Olympia Snow (R) unexpectedly announced Tuesday that she would retire, the Progressive Change Campaign Committee, a liberal PAC, launched an effort to recruit Rep. Chellie Pingree (D-Maine) for the race to replace her.

Snowe's reelection had been considered a sure thing, but without the popular senator in the race, Democratic prospects for overtaking the seat increased dramatically.

Pingree left the door open to seeking the Senate seat Tuesday in a statement applauding Snowe's service in the Senate.

"This upcoming election is critical to the future of our working families around the country, and in the coming days I will carefully consider how I can best serve the people of Maine," Pingree said.

PCCC promotes liberal candidates for Congress and launched a similar effort to recruit Democrat Elizabeth Warren into the Senate race in Massachusetts and has raised money on her behalf.

"Chellie Pingree took on corporate money in politics as the head of Common Cause and then helped lead the fight for public funding of campaigns in Congress," PCCC's co-founders wrote in an email to supporters. "She also worked hand-in-hand with us in the fight for a public health insurance option."