Phil Burress, president of Citizens for Community Values (CCV), warns Ohio politicians against backing gay marriage.

Burress and his organization led the campaign to approve Ohio's 2004 constitutional amendment which prevents the state from recognizing any relationship other than a heterosexual marriage.

“Any candidate on the wrong side of the issue will not get elected,” Burress told Dover-New Philadelphia-based Times Reporter.

Burress' comments come as a second prominent Ohio Republican is expected to endorse a 2014 campaign to legalize such unions in Ohio.

Jim Petro, Ohio's former attorney general, is expected to make an announcement on Monday.

(Related: Former Ohio AG Jim Petro to back 2014 gay marriage ban repeal effort.)

Petro told The Columbus Dispatch that he had a change of heart on the issue after his daughter Corbin married her wife last year in Massachusetts.

In March, Ohio Senator Rob Portman endorsed marriage equality in much the same way, crediting the coming out of his son Will for changing his position on the issue, though Portman has said that he does not plan to campaign in favor of changing Ohio's law.

Burress argued that legalizing gay nuptials would lead to polygamy.

“Ask the question, how do you prohibit polygamy?” Burress said. “Or anything? You've gotta give them anything they want. When you start using words like 'equal protection,' or when you can say there's discrimination, what are you going to do for bisexuals? They have to have a man and a woman to make them happy.”