In a widely expected move, independent Senator-elect Angus King of Maine announced Wednesday that he will join the Democratic Senate caucus, bringing the Democrats to a 55-senator majority in the new Congress, which convenes in January.

A former governor of Maine, King ran as an independent to fill the Senate seat being vacated by centrist Republican Sen. Olympia Snowe.

J. Scott Applewhite / AP Sen.-elect Angus King, I-Maine, center, the former governor of Maine, arrives on Capitol Hill in Washington, Tuesday, Nov. 13,2012.

“The outcome of last week’s elections in some ways makes this decision relatively easy,” King told reporters at a Capitol Hill press conference. “In a situation where one party has a clear majority and effectiveness is an important criteria, affiliating with the majority makes the most sense. The majority has more committee slots to fill, has more control over what bills get considered and more control over the Senate’s schedule.”

King said he’d conferred with Senate Majority Leader Harry Reid and former Senate Majority Leader George Mitchell, a Maine Democrat, before making his decision, but not with Senate Republican Leader Mitch McConnell. He did confer with Sen. Roy Blunt, R-Mo., the Senate GOP conference vice chairman.

He said his conversations with Reid and with independent senators Joe Lieberman of Connecticut and Bernie Sanders of Vermont, who caucus with the Democrats, reassured him that “my independence would be respected and that no party-line commitment would be required or expected.”

King said he’d asked Reid for a spot on the Senate Finance Committee, its tax-writing panel, “but there were no promises made… He pointed out to me that it took Sen. Kerry 14 years to get on the Finance Committee so it might be somewhat unlikely for a first-year senator to achieve that.”

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He said that “by associating myself with one side I am not in automatic opposition to the other.”

On the question of the Senate filibuster rule -- which allows the minority party to insist on 60 votes before a bill can move forward or a nomination come up for vote -- King said that although he represents a small state and the filibuster is “designed to protect the interests of small states,” that “its use in recent years has been excessive and I hope to talk with other senators who are more expert in this matter to find a solution that would limit its use as a tactic of delay and prohibiting action, but at the same time protect the interests of the states."

Since President Barack Obama was first elected, Republicans have used the filibuster to stymie some of his nominees and to make it impossible to enact tax increases proposed by the Democrats.