It is also a FACT that there are federal aspects to marriage whether people like it or not because people move from state to state.
Another FACT is the homosexuals have the exact same marriage rights as everyone else and they always have. There is NO LAW that prohibits homosexuals from being married. Moreover, it has ALWAYS been an option for homosexuals to enter into legal partnerships with each other.
Libertarians are the ultimate statists, they worship the utterly false idea of "states rights" and are all to happy to place these "states rights" over our rights. Under the libertarian mantra a state should have the "right" to allow incestuous marriage on any level, polygamy, infanticide and any other form of depravity it wants. The conservative movement needs to sever its relationship with libertarians and it needs to happen immediately.
I agree with your entire post. I have a strong libertarian bent when it comes to the federal govt trying to dominate me, but I do try and balance that bent with the understanding that for my country to be prosperous we do need some limits.
Thinking about this issue from a Christian perspective I get angry with our Pastors and Priests. They have done a terrible job educating Christians why Marriage is so important and is a reflection of the faith we claim. As a result, we now have a country that sees nothing wrong with validating an immoral relationship as normal. As John McCarthur preached a couple weeks ago we truly have embraced Romans chapter 1.