Conservative commentator John Calvin “Cal” Thomas has argued that legalizing gay marriage will lead to marriages between adults and children.

The syndicated columnist made his claims during an appearance on the Christian televangelist network Daystar.

Marriage equality, Thomas said, undermines “all of human history.”

“Look at Mesopotamia. Look at the Roman Empire, which collapsed from within through moral impurity before they were conquered from without. And that's my great fear. I don't fear the Russians or the fundamentalist Muslims as much as I fear ourselves,” Thomas answered when asked, “What can be done about the federal judges that override the majority of voters on marriage?”

“We are committing moral suicide in this country: 55 million dead babies through abortion and counting; we're mainstreaming same-sex marriage, the polygamists are right behind.”

“You have the people who believe in adult-child marriage, they already do this in certain Muslim countries, these people want the rights as an adult to marry a child,” Thomas added. “So all I'm asking, and what I do in debates is say, if the line has shifted now and we accept same-sex marriage, where would you then draw the line and on what basis? It's all about the polls, feelings and the culture at the time, it's not about established truth and real history.” (The video is embedded on this page. Visit our video library for more videos.)