RALEIGH, N.C. (AP) -- The national debate over gay marriage has turned its attention South.

North Carolina could be the next state to pass a constitutional amendment defining marriage as solely between a man and a woman. Voters are casting their ballots Tuesday.

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.

People also responded with marches, television ads and speeches, including one by Jay Bakker, son of televangelists Jim and Tammy Faye Bakker. She died in 2007.

The Rev. Billy Graham was featured in full-page newspaper ads supporting the amendment. Other backers have arranged sermons in churches and run their own television ads.

Experts expect the measure to pass.