The latest development in the race for Olympia Snowe's (R) Senate seat: After former Gov. Angus King (I) decided to make a bid for the seat, Dem Congresswoman Chellie Pingree (D) now has decided NOT to run.
A Democratic operative with knowledge of the situation tells NBC News that Pingree saw polling showing that a three-way race -- involving Pingree (D), King (I), and a Republican -- could throw the race to the GOP candidate, allowing the Republican Party to hold on to the seat.
The Democratic operative stresses that Pingree made this decision on her own, and that Democratic leaders have not reached out to King to get an assurance that he would caucus with the Democrats.
However, the ASSUMPTION is that the popular King -- who supports abortion rights, who backed Obama in '08 but George W. Bush in 2000 -- would either caucus with the Democrats or be a strict independent, if elected.
And it appears Democrats are willing to bet on that assumption.
"The best outcome for Senate Democrats is for King to quickly coalesce support among independents and Democrats, and eliminate any chance Republicans have to even be competitive in this race," the Democratic operative tells NBC News.
Republicans also seem to be be assuming King will caucus with the Democrats. "The decision by national Democrats to throw Chellie Pingree and other proud Democratic leaders in Maine aside, in favor of an 'independent' who supported President Bush in 2000, makes clear they are more concerned with holding onto power in Washington, than trying to advance their own party's principles," National Republican Senatorial Committee executive director Rob Jesmer said in a statement. "This is just the latest backroom deal we've seen from national Democrats and it adds to the cynicism that voters in Maine and around the country rightfully feel towards those running Washington these days."
Interestingly, liberals who had cheered a Pingree candidacy aren't upset by the news.
Said Adam Green of the Progressive Change Campaign Committee: "Chellie Pingree would have been a bold progressive fighter in the Senate, and we are confident that she will be when Susan Collins retires. Angus King was willing to create a three-way race that handed this Senate seat to a far-right Republican -- a precise repeat of what happened in Maine's 2010 three-way gubernatorial race. Chellie Pingree's decision was based on what is best for the people of Maine and the future of progressive causes, not based on what was best for herself, and we look forward to continuing our work with her around progressive fights in Congress."