BANGOR, Maine — Advocates for same-sex marriage were dealt a blow Tuesday when voters in North Carolina passed a constitutional amendment that not only banned gay marriage but outlawed civil unions and domestic partnerships as well.

So what does North Carolina’s 61 percent to 39 percent vote mean for Maine, which will vote on same-sex marriage later this year?

“It’s a continuation of what we’ve seen whenever voters weigh in on the marriage issue,” said Carroll Conley, head of the Christian Civic League of Maine and the Protect Marriage Maine political action committee. “We’ve seen judges and legislatures create momentum toward a change in cultural status, but voters have consistently shown a discomfort for redefining marriage.”

David Farmer, Bangor Daily News columnist and a spokesman for Mainers United for Marriage, the group leading the campaign to allow same-sex marriage in Maine, said what happened in North Carolina doesn’t change his group’s efforts.

“We were already very motivated,” he said. “We know what we need to do to be successful and that’s to continue to have one-on-one conversations with Mainers.

“It’s dangerous to draw too many parallels with North Carolina. We were hoping for them and we’re saddened by the outcome, but Maine and North Carolina are very different places.”

More relevant, Farmer said, is New Hampshire, where the Republican-controlled Legislature recently defeated an attempt to overturn a same-sex marriage law.

Conley said he expected same-sex marriage supporters in Maine to downplay any similarities with North Carolina but pointed out that voters still have not approved same-sex marriage laws in any state.

Maine could be the first this November when voters will be asked for the second time in three years to weigh in on same-sex marriage. In 2009, Mainers voted 53-47 to overturn a law passed by a Democratic-controlled Legislature allowing same-sex marriage.

Same-sex marriage supporters nationwide have made the argument that the tide is turning in favor of equality. Many polls seem to support that. A recent Gallup survey showed that about 50 percent of American believe same-sex couple should be allowed to marry, while 48 percent say such marriage should not be legal.

But that support hasn’t translated into votes.

Still, the demographic makeup of North Carolina — not quite in the conservative Deep South but on the border — is different from Maine. Of the six states that allow same-sex couples to marry, five are in the Northeast.

“We’ve seen this play out more in the Northeast and the dire consequences from opponents of same-sex marriage haven’t come true,” Farmer said.

The debate over same-sex marriage has intensified nationally in recent days, in part because of what has happened in North Carolina.

President Barack Obama said in an interview on Wednesday with ABC News that he now supports same-sex marriage, reversing a position he has held since he took office. During his 2008 presidential campaign, Obama said he supported civil unions but not necessarily marriage for same-sex couples.

Vice President Joseph Biden said in a interview on Sunday that he was “absolutely comfortable” with same-sex marriage. Education Secretary Arne Duncan also has said publicly that he supports gay marriage.

Although Obama said he supports same-sex marriage, he still thinks it should be left up to states to decide. Many already have.

North Carolina became the 31st state to pass a constitutional amendment that defines marriage as between a man and a woman.

Connecticut, Iowa, Massachusetts, New Hampshire, New York, Vermont and the District of Columbia allow same-sex marriage.

The Washington state Legislature passed a law in February that legalized same-sex marriage but opponents are hoping voters get a chance to overturn that law. Similarly, Maryland passed a law recently that allows same-sex couples there to wed, but that may go to a statewide referendum as well.

Later this year, voters in Minnesota will consider a constitutional amendment similar to the one that passed in North Carolina on Tuesday.