Maine’s Republican U.S. Sen. Susan Collins won an endorsement Friday from independent Sen. Angus King, support she warmly welcomed but did not request and may not need in her run for a fourth term.

With Collins holding a dominant lead in fundraising and polling over Democratic challenger Shenna Bellows, the focus shifted to King, who continues to brandish his independent credentials. The endorsement was his first as a member of Congress. It took just a few hours for the Brunswick resident to make his second.

Within hours of praising Collins as a “model senator” during a press event at the Margaret Chase Smith Library in Skowhegan, King went to Concord, N.H., to endorse U.S. Sen. Jean Shaheen, a Democrat whose three terms as governor of the Granite State overlapped King’s two terms as Maine’s governor.

The mini endorsement tour is likely to spur scrutiny of King’s political positioning as the congressional mid-term elections loom.

Early national tracking polls show that Republicans have a decent chance of taking control of the Senate. King, who caucuses with Democrats, touched off a wave of speculation in April when he suggested to the Washington-based publication The Hill that he might caucus with Republicans if they win the majority in November.

Asked Friday about joining the Republicans, King repeated earlier statements that he would base his decision on the best interest of Mainers.

POISED TO CHANGE?

His endorsement of Shaheen is likely to counter claims that King is poised to change caucuses.

Bellows would not say that King’s endorsement of her opponent was a deliberate political calculation, but she repeatedly alluded to the prospect of a Republican takeover in the Senate.

“Angus called me (Thursday) night and told me it wasn’t personal,” Bellows said. “I agree with him. These decisions about who to endorse, who to vote for aren’t personal.

“I think who to support in the U.S. Senate is about much more than either of us,” she said. “It’s about the party that will be in control in the Senate and the future of our country.”

King said all the speculation is misguided.

“They’re overthinking it,” he said. “There’s no deep personal motive here. It doesn’t have anything to do with me.”

Larry Sabato, director of the University of Virginia Center for Politics, said King’s endorsement of Collins made sense, given that the two Maine senators have a well-established working relationship. Sabato said both will benefit from Friday’s announcement.

“Collins is bound to win, but I’m sure she welcomed the endorsement because she is literally the only Republican (running for re-election) in a state President Obama won,” Sabato said. “I don’t think she has any problems at all anyway, but it’s always nice to have that added security.”

WORKING RELATIONSHIP

Collins and King differ on a number of issues, particularly the Affordable Care Act, but they have forged a working relationship and their political offices often send joint statements. The senators created a “Gang of 14” to address the government shutdown last year and worked together on a student loan bill. They also joined forces to ensure that the Navy agreed to build an extra destroyer at Bath Iron Works, one of Maine’s largest employers.

King praised Collins on Friday for her work ethic, intelligence and integrity. “She always puts Maine and the country first and isn’t afraid to cross party lines to get things done,” he said.

Collins said she was “delighted and honored” to have King’s backing, even though she didn’t ask for it. She said King recently came to her Senate office after a long day of hearings on the Senate Intelligence Committee, on which the two serve, to offer his endorsement.

““We have worked very closely together in the Senate,” she said. “He’s been ready to work and he really cares about this state and he helped create a bridge of the partisan divide in the Senate, which so often leads to excessive gridlock and excessive partisanship.”

King said the people of Maine should know that the bipartisanship displayed by Collins — and, in turn, his endorsement of her candidacy — is not a common political occurrence. In many states, he said, senators are rivals and race each other to be the first with important announcements. He said he and Collins have a joint letterhead and their press releases go out together.

“That’s very unusual, but we think it’s important — it gives Maine umph,” King said. “We’ve been able to work together and that’s been a real delight for me. She does what she thinks is right on behalf of the state of Maine and the United State of America and that’s exactly what we need in the United States Senate.”

King said they chose the Margaret Chase Smith Library for Friday’s announcement in part because Collins occupies Smith’s seat in Congress and because she was inspired early in life by the senator from Skowhegan.

“We’re here on hallowed ground in Maine, the home of Margaret Chase Smith,” King said. “We both had a long standing relationship with Margaret Chase Smith.” Smith served four terms in the House, then in the Senate from 1948 to 1972. She died in 1995.

Collins agreed. “What better place for this announcement to be made,” she said. “The theme today is bipartisanship, something that we need more of in Washington. I think the setting is appropriate. The theme is perfect And it reflects the approach to government that both Angus and I have brought to the Senate.”

King told the Portland Press Herald that he made similar offers to other members of Congress. He would not say whom. He also declined to say whether he would make an endorsement in Maine’s gubernatorial race.

The three-way race for governor includes two candidates for whom King has expressed admiration, Democratic U.S. Rep. Mike Michaud and independent Eliot Cutler. King endorsed Cutler late in the 2010 campaign. He said Friday that he hasn’t decided whether he will get involved this time.

“There’s a lot of time before the election,” he said.

Morning Sentinel Staff Writer Doug Harlow contributed to this article.Steve Mistler can be contacted at 791-6345 or at:[email protected]Twitter: @stevemistler