Independent Angus King celebrates under a splash of champagne after winning the Senate seat. (AP Photo/Robert F. Bukaty)

Political observers expect that Angus King, Maine's independent former governor who won a decisive victory Tuesday night, will caucus with Democrats when he comes to Washington, giving the party another seat as part of what promises to be a slim majority.

King, who served two terms as governor until 2003, ran as an independent and maintained throughout his campaign that he hadn't decided which party he would choose, saying he would ultimately decide based on the best interests of his state.

Nothing has changed tonight.

Reached Tuesday evening, a King spokeswoman said those awaiting King's decision will have to wait longer.

"You need to give us a day before we can talk," said spokeswoman Crystal Canney.

Despite his coyness, it is difficult to believe that King would join with Republicans, both because their attempts to retake the majority are out of reach and because the GOP and conservative groups spent millions of dollars on television attack ads against him.

King is succeeding Sen. Olympia Snowe (R-Maine), whose surprise decision to retire this year seriously complicated – and may have ultimately upset -- the GOP’s chances of retaking the Senate majority.