Republican Sen. Rand Paul of Kentucky, who describes himself as a libertarian, said Wednesday that he opposed the Defense of Marriage Act (DOMA) because it could unintentionally result in same-sex marriage becoming legal.

"I believe in traditional marriage," he said during an interview with Bryan Fischer of the American Family Association. "I really don't understand any other kind of marriage. Between a man and a woman is what I believe in, and I just don't think it is good for us to change the definition of that."

Paul noted that his state, Kentucky, had approved a constitutional amendment to prohibit same-sex marriage. He said he was "not sure" about DOMA, but warned the federal law could result in conservatives losing "the battle for the whole country."

Paul said marriage rights should be decided state-by-state rather than nationally so that "urban centers" couldn't dictate the law.

President Barack Obama in 2011 directed the Department of Justice to stop defending a key portion of DOMA in court because it was unconstitutional. The law prohibits legally married same-sex couples from receiving federal marriage benefits.

The U.S. Supreme Court is expected to rule on the constitutionality of DOMA later this year.

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