On the third day of his campaign to win the 2012 GOP nomination for president, Rick Santorum returned to familiar territory: gay marriage.

When CNN's John King asked Santorum if as president he would back a federal amendment banning gay marriage, the former senator dived head first into a nearly 2-minute rant on the subject.

“I support a constitutional amendment to ban same-sex marriage,” Santorum told King. “I think that marriage should be a consistent thing across the country. Marriage is the union of one man and one woman. It's essential for the family. It's essential for the stability of our culture to make sure that children are given the best hope, which is a mom and dad. And if we lower our sights for those children we're robbing children of – many children – of the potential of having a mom and a dad by changing the standard of what society believes in.”

“I think that's important. And I also think its important from the standpoint of religious liberty and the standpoint of what our children are going to be taught in school.”

“Every time this issue has come up on the ballot – California to Maine – people have said, 'Well this is going to pass.' In places like this, polls show people very much in favor of changing the traditional marriage definition, and it's lost every time. Why? Because once people realize the consequence to society of changing this definition – it's not that we're against anybody. People can live the life they want to live. They can do whatever they want to do in the privacy of their home with respect to that activity. But now you're talking about changing the laws of the country and it's going to have a profound impact on society, on faith, on education. And once people realize that, they say, 'You know what, we respect people's right to live the life they want to lead, but don't try to fundamentally change how society functions by changing that definition.'” (The video is embedded in the right panel of this page.)

In launching his official presidential bid, Santorum said people would respect him because he's remained true to what he believes. That, ostensibly, includes his opposition to gay and lesbian couples marrying.