After a decisive victory in the race to succeed retiring Sen. Olympia Snowe, independent Sen.-elect Angus King will travel to Washington next week to start the process of determining his place in an institution he’s vowed to fix and to start conversations that could answer the question of with whom he’ll caucus.

The former two-term governor and Brunswick resident learned at about 8 p.m. of his victory over Republican Charlie Summers, Democrat Cynthia Dill, Harpswell Libertarian Andrew Ian Dodge and fellow Brunswick Independent Danny Dalton.

Unofficially, King captured about 53 percent of the vote, to Summers’ 31, a margin of about 140,000 votes. Dill garnered about 13 percent according to the Bangor Daily News.

King waded through an appreciative crowd about 35 minutes after his victory had been declared.

As he made his way from the back of the room toward the stage, shaking hands and exchanging well-wishes as he went, the screel of bagpipes mingled with a video screen that played campaign highlights to the soundtrack of Van Halen’s “Right Now.”

Several times, the crowd burst into chants of his name.

Once on the stage, however, King grew solemn. He referred to Maine’s slogan of “Dirigo,” a Latin term which translates to “I lead.”

“Tonight,” the former governor said, “I think we should change that slogan to ‘dirigimus,’ which means ‘we lead.’”

During his acceptance speech, King sarcastically thanked right-wing political strategist Karl Rove for helping to swing support his way. He attributed the backlash to millions of dollars in “Super- PAC” funded attack ads that played in constant rotation on state television and radio stations. He congratulated voters on their willingness to choose optimism over fear and division.

“Sometimes debate can go too far and become difference for the sake of difference and argument for the sake of argument,” he said. “When this happens, we are all the poorer for it.”

Near the end of his speech, King alluded to the bipartisanship which characterized his campaign. He so far has refused to say with which party he would caucus, but King threw a peace offering of sorts to the GOP when he cited Abraham Lincoln’s Gettysburg Address as a pinnacle of political vision that transcended party ties.

“Tonight, Maine sent an important message to the rest of the country,” King said.

“Tonight, ‘We lead.’”

Tuesday’s election helds implications for control of the U.S. Senate.

It’s widely assumed that King would caucus with Democrats, especially after being subjected to millions of dollars of negative ads sponsored by conservatives and GOP super PACs.

But the former Democrat continued play his cards close to his vest. “I want to be the most effective senator on behalf of Maine so I’ll be talking to anyone who wants to chat,” he said.

King was inspired to run because Snowe described the Senate as broken and he cast himself as unbeholden to parties and able to broker compromise. But he’s realistic about what he can accomplish.

“As I’ve said repeatedly, I’m neither naive nor arrogant enough to think I can go down there and do it all myself, and I don’t think they’re going to ask me how to run the place,” he said. “But I do think we’re going to begin the process that leads to real change and makes the place work for the people.”

Snowe, who has known King for years, called him to offer her congratulations and to offer to assist him with a smooth transition. Collins said she and King will get together to discuss committee assignments “and how we can work together to meet the challenges facing our state and our nation.”

The outsized amount of outside spending underscored the stakes in the closely divided Senate, where before the election Democrats held a 51-47 majority with two independents who caucus with them.

Summers had vowed to restore “fiscal sanity” by cutting spending, reducing taxes and bringing down the federal debt. Dill campaigned as a progressive who was eager to continue Obama’s agenda.

Summers, in his concession, said he wouldn’t have changed anything about his campaign “except for the outcome.” He offered his full support to King and added, “Now is the time to stand behind our elected leaders and wish them well.”

Dill said she was proud to be an example for young women and looked forward to the day when women make up a bigger share of the Senate membership. “I hope that my candidacy will inspire women and girls to make their voices heard, no matter how high the obstacles,” she said.

King, 68, of Brunswick, was targeted beginning in the summer with a TV blitz during the Olympics in which the U.S. Chamber of Commerce described him as “king of spending” and “king of mismanagement.”

The primarily three-way race created unusual dynamics in which a GOP-led group spent heavily to prop up Dill in hopes of keeping Democratic votes away from King. Later, the Democratic Senatorial Campaign Committee spent money to attack Summers after polls showed him gaining momentum against King.

The GOP was virtually assured of keeping the Senate seat before Snowe abruptly abandoned the race. Her announcement in late February, a week after her 65th birthday, caused a scramble. Summers, 53, of Scarborough, and Dill, 47, of Cape Elizabeth, won their crowded primaries.

DAVID SHARP of The Associated Press and Times Record staff writer JT Leonard contributed to this report.