Popular former Maine Gov. Angus King (I) tonight comfortably won the Pine Tree State’s open Senate seat, currently held by moderate Republican Sen. Olympia Snowe, who is retiring.

The Associated Press called the race. King beat Maine Secretary of State Charlie Summers (R) and state Sen. Cynthia Dill (D).

King hasn’t said with which party he will caucus, but he is widely expected to cast his vote for Senate Majority Leader Harry Reid (D-Nev.). The National Republican Senatorial Committee spent a not insignificant amount of money against King, lobbing potent attack ads his way. National GOP third-party groups also tried to knock King down and boost Summers.

But Mainers have fond memories of King’s tenure as governor, and the ads were never really able to break through to the electorate. Indeed, despite Republican efforts to make this race competitive, the seat was King’s from the moment he announced his candidacy. He declared his intention to run at Bowdoin College in Brunswick, where he was a lecturer who taught a course on leadership.

Dill, a weak candidate with progressive positions out of step with the state, had nominal support from local Democrats, but she never got the nod from the Democratic Senatorial Campaign Committee, which always tacitly supported King.

And Summers, who given his strength as a candidate well could have been a Senator in another state, was never able to really grow beyond his GOP base.

To an electorate unhappy with the status quo in Washington, D.C., and suspicious of partisans, King made a strong case that he could be an independent voice who could start to break through the gridlock in the Capitol.

On the campaign trail, King was friendly, thoughtful, inquisitive and good-humored. When pressed on his party affiliation, he said he voted for George W. Bush in 2000 and Barack Obama in 2008. King called himself “a moderate, a centrist.”