New Hampshire legislators were also poised to send a gay marriage bill to their governor, who hasn't indicated whether he'll sign it. If he does, Rhode Island would be the region's sole holdout.
The Maine Senate voted 21-13, with one absent, for a bill that authorizes marriage between any two people rather than between one man and one woman, as state law currently allows. The House had passed the bill Tuesday.
Democratic Gov. John Baldacci, who hadn't previously indicated how he would handle the bill, signed it shortly afterward. In the past, he said he opposed gay marriage but supported civil unions, which provide many benefits of marriage.
Debate was brief. Senate President Elizabeth Mitchell, D-Vassalboro, turned the gavel over to an openly gay member, Sen. Lawrence Bliss, D-South Portland, to preside over the final vote.
Republican Sen. Debra Plowman of Hampden argued that the bill was being passed "at the expense of the people of faith."
"You are making a decision that is not well-founded," warned Plowman.
But Senate Majority Leader Philip Bartlett II said the bill does not compel religious institutions to recognize gay marriage.
"We respect religious liberties. ... This is long overdue," said Bartlett, D-Gorham.
Maine is now the fourth state in New England, to allow same-sex marriages. Connecticut enacted a bill after being ordered to allow gay marriages by the courts, and Vermont passed a bill over the governor's veto.
New Hampshire's House was also expected to vote on a bill Wednesday and send it to Gov. John Lynch, a Democrat.
Massachusetts' high court has ordered the state to recognize gay marriages. In Rhode Island, a bill to legalize same-sex marriage has been introduced but is not expected to pass this year.
Outside New England, Iowa is recognizing gay marriages on court orders. The practice was briefly legal in California before voters banned it.
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Eric Hosmer and the San Diego Padres finalized their $144 million, eight-year contract Monday night.
The summits of Birch Hill and Palomar Mountain saw a dusting of snow Monday, and other San Diego County mountains and valleys experienced less than a quarter-inch of rain.
Local mothers fed up with school violence are calling for tougher gun laws in the wake of the Florida high school shooting.
A North County eatery is believed to be the first restaurant in San Diego County where parents can have it all - great food, alone time and supervised onsite child care.
According to Scripps Ranch residents, for weeks they've been waking up to deep scrapes and scratches that someone keyed in their vehicles, and on Sunday an arrest was made in connection with the incidents.
A man accused of carrying out an armed robbery in the Mountain View area was place under arrest Monday.
A woman was seriously hurt after a car driven by a 52-year-old man veered off a road and onto a sidewalk Sunday in the Valencia Park area, police said.