Marriage, though, was probably started for totally secular reasons. Contracts that can be considered equal to today's marriage papers have been around for so long. It was the 24th Council of Trent, in around 1560, which brought the church into marriage. Prior to that, marriage was a secular institution entirely overseen by the local government.
This means that anyone who doesn't want to be religiously married would have to go through a common-law marriage instead, which makes taxes and other aspects of married life more difficult.
Mostly I'm confused that A) something so backwards is attempting to be passed in an attempt to stop gay marriage and B) these people don't realize how this would also hurt themselves. Many people already married would now be considered common-law marriages, leading to all sorts of troubles. The whole idea is "Oh we'll let the churches decide who gets married" with him assuming every church is bigoted as he is. But the thing is, there are many LGBT friendly churches and so he's effectively legalized gay marriage.