Republican presidential candidate Rick Santorum on Monday called for a constitutional amendment to define marriage as between a man and a woman, a position that falls to the right of the rest of the Republican field, which has largely backed leaving the subject up to states.

“We need a national standard for marriage,” the former Pennsylvania senator said at a breakfast event hosted by the Christian Science Monitor in Washington, D.C. He called it a “mistake” to let states make the decision.

“You can’t have a hodge-podge of marriage,” he said. “It just creates too much confusion out there.”