Randy Barnett over the the Volokh Conspiracy has a piece up on Gay Marriage. The core argument is that marriage is a contract between two people. The government is meddling in civil liberties of individuals when it says that they can't enter a contractual relationship. This is interesting because its conservatives who are asking for the meddling instead of decrying it as usual.
This only has one problem. Marriage is not just a contractual relationship between two people to share property and parenting responsibilities. Its a contractual relationship with society as well. Thats why marriages are public gatherings and require witnesses. Thats why businesses often recognize married couples for special benefits. If marriage were just between two people this wouldn't be a big deal and I'd be with you.
You see by granting gay marriage equal standing with straight marriage you give the gay couples the weapon of equal protection to legally compel me to violate my conscience.
I have no problem with a gay couple raising their kids or sharing property rights based on their relationship. Good for them. I don't have a problem with them assuming many of the trappings of traditional marriage.
I have a problem with them walking up to me and saying "you give this to straight couples so you have to give this to us too." Yes in a way I am talking about the freedom to discriminate. I don't hold that all discrimination is a wrong or bad. Discrimination is actually necessary like judging between right and wrong. The Sermon on the Mount tells us to discriminate wisely through even judgement without prejudice, not to be completely undiscriminating. Thats the whole point of the "pearls before swine" passage that follows the "judge not lest ye" passage.