RALEIGH, N.C. — North Carolina approved a constitutional amendment Tuesday defining marriage solely as a union between a man and a woman, becoming the latest state to effectively slam the door shut on same-sex marriages.

With most of the precincts reporting Tuesday, unofficial returns showed the amendment passing with about 61 percent of the vote to 39 percent against. North Carolina is the 30th state to adopt such a ban on gay marriage.

Tami Fitzgerald, who heads the pro-amendment group Vote FOR Marriage NC, said she believes the initiative awoke a silent majority of more active voters in the future.

"I think it sends a message to the rest of the country that marriage is between one man and one woman," Fitzgerald said at a celebration Tuesday night. "The whole point is simply that you don't rewrite the nature of God's design based on the demands of a group of adults."

In the final days before the vote, members of President Barack Obama's cabinet expressed support for gay marriage and former President Bill Clinton recorded phone messages urging voters to oppose the amendment.

Supporters of the amendment responded with marches, television ads and speeches. Church leaders urged Sunday congregations to vote for the amendment. The Rev. Billy Graham was featured in full-page newspaper ads backing the amendment.

North Carolina law already bans gay marriage, but an amendment effectively seals the door on same-sex marriages.

The amendment also goes beyond state law by voiding other types of domestic unions from carrying legal status, which opponents warn could disrupt protection orders for unmarried couples.

The campaign manager for the group that opposed the amendment said the nation watched North Carolina on Tuesday night, wondering how the anti-forces came through.

"I am happy to say that we are stronger for it; we are better for it; our voices are louder now," said Jeremy Kennedy of Protect All NC Families. "We have courage like we never had before, and we have strength to continue on."

Both sides spent a combined $3 million on their campaigns.

Six states – all in the Northeast except Iowa – and the District of Columbia allow same sex marriages. In addition, two other states have laws that are not yet in effect and may be subject to referendums

The North Carolina amendment was placed on the ballot after Republicans took over control of the state Legislature after the 2010 elections, a role the GOP hadn't enjoyed for 140 years.

Joe Easterling, who described himself as a devout Christian, voted for the amendment at a polling place in Wake Forest.

"I know that some people may argue that the Bible may not necessarily be applicable, or it should not be applicable, on such policy matters. But even looking at nature itself, procreation is impossible without a man and a woman. And because of those things, I think it is important that the state of North Carolina's laws are compatible with the laws of nature but, more importantly, with the laws of God."

Linda Toanone, who voted against the amendment, said people are born gay and it is not their choice.

"We think everybody should have the same rights as everyone else. If you're gay, lesbian, straight – whatever," she said.

North Carolina is the latest presidential swing state to weigh in on gay marriage. Florida, Virginia and Ohio all have constitutional amendments against gay marriage, and Obama's election-year vagueness on gay marriage has come under fresh scrutiny.

Obama, who supports most gay rights, has stopped short of backing gay marriage. Without clarification, he's said for the past year and a half that his personal views on the matter are "evolving."

Later Tuesday, Obama's campaign said he was "disappointed" with the amendment. Obama campaign spokesman Cameron French said in a Tuesday statement that the ban on same-sex unions is "divisive and discriminatory." Same-sex couples deserve the same rights and legal protections as straight couples, French said.

Education Secretary Arne Duncan stated on Monday his unequivocal support for same-sex marriage, a day after Vice President Joe Biden said he is "absolutely comfortable" with same-sex married couples getting the same rights at heterosexual married couples.

One fault line that could determine the result is generational. Older voters, who tend to be more reliable voters, were expected to back the amendment.

State House Speaker Thom Tillis, a Republican from a Charlotte suburb, said earlier in the day that even if the amendment passed, it would be reversed as today's young adults age – within 20 years. "It's a generational issue," Tillis told a student group at North Carolina State University in March about the amendment he supports.

"Also, that amendment is against women, I believe, because also underneath the amendment, other laws are saying that people who aren't married at all, they can't file for domestic abuse cases, if they're living with their significant other. Which is wrong," Toanone said.

In North Carolina, more than 500,000 voters had cast their ballot before Tuesday, which was more than the 2008 primary when Obama and Hillary Clinton were fighting for the Democratic presidential nomination. Both sides said that bodes well for them.

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Associated Press writers Allen Reed, Allen G. Breed, Emery P. Dalesio and Gary D. Robertson contributed to this report.

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Martha Waggoner can be reached at http://twitter.com/mjwaggonernc

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  • Obama For America N.C. Press Secretary Cameron French

    <blockquote>"The President has long opposed divisive and discriminatory efforts to deny rights and benefits to same sex couples. "He believes the North Carolina measure singles out and discriminates against committed gay and lesbian couples, which is why he did not support it. President Obama has long believed that gay and lesbian couples deserve the same rights and legal protections as straight couples and is disappointed in the passage of this amendment. On a federal level, he has ended the legal defense of the Defense of Marriage Act and extended key benefits to same-sex partners of federal employees."</blockquote>

  • DNC Chairwoman Debbie Wasserman Schultz

    <blockquote>"The passage of Amendment One in North Carolina is very disappointing. It unfairly singles out gay and lesbian Americans and is discriminatory. I'm proud that President Obama opposed Amendment One, as he has long believed that gay and lesbian couples deserve the same rights and legal protections that straight couples already enjoy. "While the passage of tonight's amendment is disappointing, it does not erase the incredible progress that gay and lesbian couples have made under the President's leadership. From putting an end to the legal defense of the Defense of Marriage Act in the courts and endorsing legislation to repeal it, to making sure that same-sex couples have equal hospital visitation and medical decision-making rights and extending key benefits to the same-sex partners of federal employees, we have taken great strides forward. "The choice is clear. The President has fought on behalf of LGBT Americans while Mitt Romney has supported inequality and discrimination. Romney has said we should write discrimination and inequality into the Constitution, and he has funded efforts in states that have adopted marriage equality to roll back these rights. On this and so many other issues, Romney, like Amendment One, would take us in the wrong direction."</blockquote>

  • Eric Wolfson, president of Freedom To Marry

    <blockquote>"As momentum for the freedom to marry continues to grow in the rest of the nation, today's vote is a painful reminder of what happens when a preemptive ballot-measure is stampeded through before people have had enough time to take in real conversations about who gay families are and why marriage matters to them. This amendment is a last gasp of discrimination that will cause real harm to families, communities, and businesses in North Carolina, but says little about the prospects for a better outcome in battles to come in states where there has been greater visibility for loving and committed couples and those who get to know them. And even in North Carolina, the long-term effect of this nasty attack will be to spur more conversations and open more hearts, helping more people rise to fairness and support for the freedom to marry."</blockquote>

  • Tony Perkins, Family Research Council

    <blockquote>"We applaud North Carolina voters for joining voters in 31 other states upholding the historic and natural definition of marriage as the union of one man and one woman. "At every opportunity, the American people have demonstrated a deep appreciation for the unique benefits that marriage between a man and a woman brings to families and society. They recognize that marriage is the only kind of union that results in natural procreation and keeps a mother and father together to raise the children produced by their union."</blockquote>

  • Rea Carey, National Gay and Lesbian Task Force

    <blockquote>"North Carolina has wandered into treacherous terrain with Amendment One. For all the talk of bolstering families, this measure shamefully shoves them into harm's way. "Blocking loving couples from forming legal unions like domestic partnerships, civil unions and marriage flies in the face of family values. Indeed, Amendment One defies what it means to be a family today. Many North Carolinians, including seniors, single women and children, could be placed in peril because the shrinking definition of family excludes them. Some might even be denied life-saving services like domestic violence protections. This is a brutal step backward for relationship recognition in North Carolina. "We thank all the voters who rejected Amendment One. We stand in solidarity with them and the Coalition to Protect North Carolina Families as they build on this effort to make North Carolina welcoming and safe for all."</blockquote>

  • North Carolina Democratic Party

    <blockquote>"Tonight's results are an unfortunate reminder that the fight for Civil Rights in our state is not yet over. Writing discrimination into our Constitution is wrong. The State Constitution exists to protect the rights of our citizens- not to take them away. Despite this setback, north Carolina Democrats will continue to fight for all of our citizens."</blockquote>