Ron Paul, the only GOP president candidate opposed to a constitutional amendment banning gay marriage, is wrong on the issue, Brian Brown, the president of the National Organization for Marriage (NOM), has claimed.

While the 76-year-old Paul has said he is personally opposed to gay marriage, he has also called on the government to “butt out” of the marriage business.

“I want the government out. If you're going to have government under the constitution, the states have a lot more authority than the federal government has to define it. I'd rather see it be outside of government and then we would not be arguing about this,” he told the Des Moines Register's editorial board.

In an op-ed published at the Daily Caller, Brown called Paul “wrong on marriage.”

“Paul is the only major GOP contender for president not to sign the National Organization for Marriage 'Marriage Pledge,' a document that commits signatories, if elected, to taking specific actions to protect traditional marriage,” Brown wrote. “Paul once replied 'sure' when asked by an interviewer about legalizing gay marriage for the entire country, Paul won't lift a finger to protect the definition of marriage as the union of one man and one woman.”

NOM earlier released a video attacking Paul's position on the issue.