MONTPELIER, Vt. — A sign planted outside the Vermont capitol read, "Let Love Win." For gays and lesbians seeking the right to marry, it did.

The state House on Tuesday narrowly achieved the votes necessary to override Gov. Jim Douglas' veto of a bill that allowing gays and lesbians to marry beginning Sept. 1.

The vote unleashed cheers and whistles from the ban's opponents and capped a bitter battle that revisited the pain and division preceding Vermont's first-in-the-nation civil unions law nine years ago.

"We've shown that truth and fairness and justice and love are more powerful than one man's veto pen," said Beth Robinson, chairwoman of the Vermont Freedom to Marry Task Force.

With the 100-49 vote, Vermont became the fourth state to legalize gay marriage and the first to do so with a legislature's vote. The override passed the House by the slimmest possible margin — it needed 100 votes.

Robinson sat in the packed House chamber, keeping a tally as lawmakers called out "yes" or "no." When the last vote was recorded, she took off her glasses and wiped away tears.

"It's amazing to be a part of a civil rights movement and it's amazing to realize the power that people have to make a better world," she said later.

Gay marriage supporters outnumbered opponents at the Statehouse. A sea of yellow buttons that read "From legal rights to equal rights" were visible in the gallery.

Craig Bensen, a gay marriage opponent who had lobbied unsuccessfully for a nonbinding referendum on the question, listened to the voting from outside the chamber. He said he and his fellow opponents were massively outspent in their lobbying effort.

"Given everything that was marshaled against us and all the advantages that the other side had it's not necessary a resounding victory that the other side squeaked by like this," he said.

Both opponents and proponents of gay marriage predicted the measure would embolden activists in other states, particularly since it came from a popularly elected legislature. The three other states that currently allow same-sex marriage — Connecticut, Massachusetts and Iowa — were all moved to do so through the courts.

"What may give courage to other legislatures is that this legislature managed to do it," said Boston University law professor Linda McClain, an expert on family law and policy.

Bills to allow same-sex marriage are currently before lawmakers in New Hampshire, Maine, New York and New Jersey.

The District of Columbia City Council on Tuesday moved toward recognizing gay marriages performed in other states, although the measure is subject to a review by Congress.