Texas Gov. Rick Perry has signed a pledge to support a federal constitutional amendment defining marriage as being between one man and one woman.

The "Marriage Pledge" was drafted by the National Organization for Marriage. It states that if elected president, the GOP candidate must send the legislation to the states for ratification. 

Perry must also appoint U.S. Supreme Court and federal judges who will "reject the idea our Founding Fathers inserted a right to gay marriage into our Constitution."

"Obviously gay marriage is not fine with me. My stance hasn't changed. I believe marriage is a union between one man and one woman," Perry said during a July broadcast interview with Tony Perkins of the conservative Family Research Council.

Republican candidates Rep. Michelle Bachmann and former Mass. Gov. Mitt Romney have also signed the pledge.