Marriage was created as a sexist institution to exchange property from one man to another without the woman being able to own property on her own. This existed before the Abrahamic religions and before the American government. That is "traditional marriage." If you want to allow churches to dictate marriage laws, then you are choosing sides and making us a theocracy.
Marriage has evolved many times in many ways in many places, and will continue to evolve, and religions don't have a copyright on the idea. Traditionally, most western cultures have at some point allowed one man to have several wives, because they were also traditionally considered property. Marriages have also traditionally been performed to create alliances and peace treaties. The Catholic Church didn't even recognize marriage as a sacrament until the 12th century. In early America, if a woman's husband died, and there were no living male relatives to get all the property, and she got the house and the land and the money (this was very rare, since they would prefer to give it to any brother, father, or cousin they could find), they would call her a witch and kill her. (If we let women own land, we might have to let them vote, and that was a really scary idea back then.)
As far as the American government is concerned, marriage needs to be legal for everybody or illegal for everybody. The churches can decide whether or not to recognize certain marriages, but they shouldn't have any power to get the laws changed so they get special treatment. This would be done the same way different Christian churches won't recognize divorces in the same way the government does.
In the U.S., the majority is not supposed to have power to vote away the rights of the minorities. That's where majority rule ends and becomes tyranny, and is one of the reasons we have a Supreme Court to stop the majority when they go mad with power. There are still people who think blacks and whites marrying each other is some gross unholy sin, and there was a time when they were the majority and that was the law. Those laws weren't repealed until the Supreme Court got rid of them in 1967, with the Loving v. Virginia case. I believe that's how the gay marriage issue will end up, and then in 40 years kids will look back at gay marriage laws and think they were as ridiculously ancient and unfair as anti-miscegenation laws.
Or maybe we should all fondly remember the wise words of Virginia judge Leon Bazile from 1965, 2 years before the Supreme Court overturned his decision: "Almighty God created the races white, black, yellow, and red, and he placed them on separate continents. And but for the interference with his arrangement there would be no cause for such marriages. The fact that he separated the races shows that he did not intend for the races to mix."
@OP,
Miss California said "opposite marriage" and should have lost due to that alone. She also should have just worded it better so she wasn't telling everybody else how to live. She tried to tone it down a bit by saying it's great how people can decide, but then in the next breath she decided, for everybody. And that's where she lost. It was a pretty tricky question for a beauty pageant, definitely, but at beauty pageants you're supposed to give really boring answers about world peace, no matter what the question is.
I hope somebody makes a beauty pageant mash-up video, where I can learn that most people don't have maps of opposite marriage and the Iraq.