King says he chose to caucus wtih Democrats because they now hold the majority, and Democratic Senate leaders have assured him that he would be able to retain his independence.

Maine independent Sen.-elect Angus King says he plans to caucus with Democrats. King made the announcement this morning at a news conference in Washington D.C.

King says he had several meetings with Democratic and Republican leaders leading up to his decision, which comes as no surprise to many political observers, who have long speculated that King would caucus with Democrats.

King says some Republicans have expressed disappointment, but he says "joining one side doesn't mean I'm in opposition to the other." He says he hopes he can serve as a "bridge" between the two parties.

The former Maine governor said he had to choose a side in order to serve on Senate committees. He said he chose to caucus with Democrats because the party currently holds the majority in the Senate.

King says he also got personal assurances from Senate Democratic leaders that he would not be expected to "toe the party line, and that was important to me."

Susan Sharon contributed to this story.