So, you're against the state's rights when it's one of your issues.
There is a difference between regulating something and defining something. States may have the right to regulate the drinking age, but that doesn't mean that they have the right to define the chemical composition of alcohol or define the meaning of "100 proof". By the same token, states have the right to 'regulate' marriage in terms of the restrictions that they put on it, but that doesn't mean that the states have the right to DEFINE marriage. They are two entirely different things. One belongs at the state level, and the other, apparently, needs to be done at the federal level.
That is a fair enough argument. I'm not opposed to a DOMA. I see it as dead in the water, though. So pretending that I would get it done as I campaigned for President (and I'm still not sure how a President gets an Amendment passed) is pandering, imo. Appointing conservative justices would accomplish far more in the long run than a currently almost hopeless chance to pass the DOMA.