RESIDENTS of North Carolina voted in favour of a constitutional amendment banning same-sex marriages and civil unions on Tuesday.
The measure was passed by 61pc against 39pc, according to preliminary results from the North Carolina State Board of Elections.
Similar state constitutional amendments have been approved in some 30 US states.
The amendment solidifies and expands already enacted North Carolina law forbidding same-sex marriage.
Money from national interest groups poured into North Carolina ahead of the election – the National Organisation for Marriage contributed $425,000 to the Vote for Marriage campaign, according to the latest reports, and the Human Rights Campaign contributed some $257,000 to the opposition, the Coalition to Protect All NC Families.
The Reverend Billy Graham, an evangelical preacher who was born and lives in North Carolina and at 93 remains enormously influential, took out full-page newspaper ads across the state supporting the ban.
"At 93, I never thought we would have to debate the definition of marriage," Reb Graham said in the ads.
"The Bible is clear: God's definition of marriage is between a man and a woman."
On the other side, former president Bill Clinton and his ex-chief of staff, Erskine Bowles, a North Carolina native, recorded telephone messages to voters urging them to oppose the measure. In a statement, President Barack Obama's campaign also opposed the amendment.
"The passage of Amendment One is a profound injustice. Singling out a class of citizens for discriminatory treatment is unfair, unlawful and violates basic American values," said Adam Umhoefer with the American Foundation for Equal Rights, a leading US group supporting gay marriage, after the vote.