Are Gay Civil Unions a National or State Issue?

In supporting Dean's position which a writer at Tom Paine opposes, Dean Defense Forces I think cites a weak precedent.

Dean makes a pretty strong case for opposing the federalization of marriage and civil union law and it is not a difficult case to make. Unlike, say, voting rights laws (and other civil rights legislation) or abortion law, marriage law is a form of contract law. And, with contract law, the Constitution forces states to generally respect contracts forged in other states. Hence, one state adopting same-sex marriage would spread it virtually nation-wide. On the other hand, if marriage law was federalized, our current Republican federal government could easily prohibit not just same-sex marriage, but the civil unions currently recognized in Vermont.

The original Brown decision called for desegregation, but didn't demand a remedy. The courts waited and gave states time to cope with civil rights. Congress also gave the nation time.

Weak and divisive. do we need a reminder of how this Brown decision played out in the courts inflaming passions for years? Dean has a better response when he says his signing gay civil unions provoked a bitter divisive outcry for a few months but now has almost disappeared, very few people end up against a law that says someone should be treated the same as you?

I support the Dean position which is that civil unions are contract law and contract law is a state issue. I also think by that argument you can have other equivalent contracts for more than two people. The counter-arguments are all religious, which is why it is wise to draw a distinction between civil unions and marriages as Dean does.