What exactly does the "sanctity of marriage" even mean.
Lets see, allowing homosexual people to get married to each other would.
1. Not effect the people that don't like it in almost any way.
2. Not effect the opponents' religion or what they believe in any way.
3. Not prohibit the opponents of it from getting married in a standard marriage in any way.
4. Would not end traditional marriage in any way.
5. Would not make the opponents of it change how they practice their own religion.
So basically they want to stop something that doesn't effect them in almost any meaningful way because it's against their own religious beliefs or just as bad because it's against tradition. That's the whole basis they want to use to restrict fair and equal rights from people. That's pathetically sad, and I've have yet to hear an even remotely good reason for why homosexual people shouldn't be allowed to get married. I don’t see this as any different than restricting any other belief system that doesn’t hurt anybody else because people don’t like it.
I'm sure if they lived in a society where the majority had different religious views than them or different values they would be screaming at the top of their lungs about how their inherent rights were being violated if they were not allowed to practice what they believed, especially when it didn't effect anybody else but themselves. That's hypocrisy for you though. For people like that it's only bad when it goes against what they believe and if tyranny works out for them they have no problem or turn a blind eye to it.
Not allowing homosexual people to get married is nothing more than forcing a religion or philosophy on somebody else plain and simple. Ironically, this is while this countries founding beliefs', the constitution, and even the religions of the people against gay marriage own deeply held beliefs being that people should be free to practice a belief system they want if it doesn't harm others.