The leader of a Christian think tank is warning that marriage between two men or two women "only brings pain and heartache."

In a video message, Tony Perkins, head of the Family Research Council — a hate group, according the the Southern Poverty Law Center -- declared that President Barack Obama's support of same sex marriage had made it a "major issue in the presidential election."

"The President has provided a clear contrast between him and his challenger Mitt Romney. Romney, who has signed a pledge to support a marriage protection amendment to the U.S. Constitution, may have been handed the key to social conservative support by President Obama," Perkins predicted.

In a second video produced by Family Research Council's Truth in Action Ministries, Perkins called on his followers to "get involved" and "vote your values."

"For nearly a generation, we've neglected marriage, leaving nearly defenseless to homosexual activists who are now trying to redefine marriage out of existence," the hate group leader explained. "Same sex marriage, it contradicts God's will as revealed in the created order, violating God’s law only brings pain and heartache. Right is called wrong; evil is called good, it is because we have wielded moral authority to the demands of special interests or the ruling of some aberrant judge. As a result, all of society suffers."

"The future of marriage is up to you, your vote can determine the language of your state constitution and the people we elect in our representative form of government will pass the laws and appoint the judges who may decide the final outcome. Get involved, vote your values, your biblical values, and make a difference."

(h/t: Right Wing Watch)