NEW YORK – Voters in Maryland, Maine and Washington state approved same-sex marriage on Tuesday, marking the first time marriage rights have been extended to same-sex couples by popular vote.

The vote was hailed as a watershed moment by gay rights activists. While same-sex unions have been legalized in six states and the District of Columbia by lawmakers or courts, voters had consistently rejected doing so. Voters in more than 30 states have approved constitutional bans on gay marriage.

“We made history and sent a powerful message that we have truly reached a tipping point on gay and lesbian civil rights in this country,” said Brian Ellner, head of the pro-gay marriage group The Four. “By winning for the first time on marriage at the ballot box, we made clear what national polls already show — that Americans support fairness and equality for all families.”

President Barack Obama this year became the first U.S. president to support gay marriage. His campaign endorsed the gay marriage measures in the three states.

In Maryland, the measure passed 52 percent to 48 percent. In Maine, voters supported the proposal 53 percent to 47 percent, with 75 percent of precincts reporting. And in Washington, a gay marriage measure was approved 52 percent to 48 percent.

Voters in Minnesota rejected a proposal that would have defined marriage solely as a heterosexual union. The constitutional amendment failed 48 percent to 52 percent.

In all four states, the marriage equality effort did better in urban areas and were less popular among rural voters.

The constitutionality of restricting marriage to unions between a man and a woman is widely expected to be taken up by the U.S. Supreme Court soon.

James Esseks, director of the ACLU Lesbian Gay Bisexual and Transgender Project, called the votes a “watershed moment” for gay and lesbian families.

“Not long ago, marriage for same-sex couples was unimaginable,” he said. “In a remarkably short time, we have seen courts start to rule in favor of the freedom to marry, then legislatures affirm it, and now the people vote for it as well.”

OPPONENTS SAY OUTSPENT

Brian Brown, president of the National Organization for Marriage – the leading group opposing same-sex marriage – said those favoring so-called traditional marriage had been outspent by a margin of at least 4 to 1.

“Our opponents and some in the media will attempt to portray the election results as a changing point in how Americans view gay marriage, but that is not the case,” Brown said in a statement. “Americans remain strongly in favor of marriage as the union of one man and one woman. The election results reflect the political and funding advantages our opponents enjoyed in these very liberal states.”

In Massachusetts, Iowa and Connecticut, laws followed court rulings that same-sex couples could not be denied marriage rights. Legislatures approved the change in Vermont, New York and New Hampshire.

Before this year, ballot initiatives banning the legal recognition of same-sex marriage had succeeded in 31 states, and no state had ever approved same-sex marriage by popular vote.

Maine voters rejected gay marriage in a referendum in 2009 by 53 to 47 percent. In Washington and Maryland, where state legislatures previously passed laws expanding marriage rights to gay and lesbian couples, it was up to citizens to decide whether to let the laws stand.

“Over these past few weeks, Marylanders joined together to affirm that for a free and diverse people of many faiths – a people committed to religious freedom – the way forward is always found through greater respect for the equal rights and human dignity of all,” Governor Martin O’Malley said in a statement.

(Reporting by Edith Honan; Editing by Cynthia Osterman and Stacey Joyce)