This is a bit of a different issue than setting local tax rates or speed limits, things that don't really matter once you cross a state boundary.
Um, what is your solution? I don't support the idea of forcing states to recognize homosexual marriages from other states through the Full Faith and Credit clause. States are not required to recognize gun permits from other states. Why should they be required to recognize homosexual marriage licenses? And if you say that we'll get a federal constitutional amendment to ban it nationwide, it would never pass. Maybe 10 years ago, but not now. The priority should be ensuring that the 44 states that don't currently allow homosexual marriage are not forced to allow it by the 6 that do. The states that don't allow homosexual marriage should not be forced to recognize it through a Supreme Court decision based on faulty constitutional principles.
Marriage, be it monogamous or polygamous, is an ancient institution that predates the nation-state, to say nothing of the welfare state, by millennium. It arose as a solution for social tensions caused by inheritance concerns, availability of women, and the stable raising of children.
The reason this has evolved into a problem is that the state (which is far too deeply involved in our lives) has gotten far too deeply involved in the business of marriage. There's too much state-derived advantage in getting married to your average homosexual or 4 wived Imam to let it go.
The solution is to leave marriage to the churches (or mosques) or the institutions that invented them, and leave the state out of it. Cultures have generally respected marriage between them, but it's never really cost anyone money before to respect someone's marriage. It does now. If you so much as question it, there's probably some hate crime violation they'll slap you with. That's the problem. With marriage as a state concern, how the state wants you to think becomes a community, social, and very personal concern to every American.
This is the trap that people who favor the state's involvement have wrought. If you feel that the state should be in the marriage business, then you're basically playing a game against people who will keep changing the rules until they win.