From a strictly logistical point of view, it's an argument to be made; anyone can get married today if they're willing to marry someone for whom they have no affection. I simply don't agree with it. I'm not religious. I was never raised in a church. So I don't hold that set of bigoted values. (From a non-religious point, everything written in Leviticus with regards to sexual congress only allows those actions between a man and his wife only at the times of month in which she's most fertile, thus leading to higher birthrates among the Jewish people should they choose to follow those rules. It's a very shrewd set of rules writing for growing political power in a world where safety in numbers was a great priority.)
Personally, I say that the Federal government removes itself from the term "marriage" and moves into strictly using the term "civil union". Then allow states to make up their minds as to what should be allowed. Eventually, those states will come around. States like MS will take a long time to come around on the finding a true state of equality, and homosexuals can then know to avoid those states should they choose to be treated like full people. And given that homosexuals have greater household incomes than straight people, the economics of such a situation will force those laggard states to catch up with the times.