Herman Cain's continued opposition to a constitutional ban on gay marriage has drawn heated words from rival Rick Santorum.

Speaking Sunday on NBC's Meet The Press, Cain reiterated his opposition to a constitutional amendment defining marriage as a heterosexual union.

Host David Gregory asked: “Would you seek a constitutional ban for same-sex marriage?”

“I wouldn't seek a constitutional ban for same-sex marriage, but I am pro traditional marriage,” Cain said.

“But you would let the states make up their own mind as they're doing now?”

“They would make up their own minds, yes,” Cain answered.

Santorum, considered the GOP field's most vociferous opponent of gay rights, hit back during a Radio Iowa interview, calling Cain's answer “sad.”

“This idea that this issue should be left to the states is the position Barack Obama takes and it's not the right position,” Santorum said. “There needs to be a uniform definition of marriage in this country.”

“Leaders should be out there advocating for what is in the best interest of our society and what's in the best interest of mothers and fathers and children and I'm going to do that. I have done it and I have done it here in Iowa and I don't know anybody else in this campaign, including Herman Cain, who has made that kind of blanket commitment to the institution of marriage and the stability of the family.”