Loving you is easy 'cause there's a rational basis for it: My apologies to Minnie Riperton, but I can't help myself. Also, I hate you Eno for making me try to remember my Con Law courses. But here goes:
First of all, Warren used a couple of analyses to make up his mind. The one that gets short shrift, but from which Ms. Ridenour's favorite sentence ("Marriage is one of the "basic civil rights of man," fundamental to our very existence and survival.") comes from is under the Due Process prong. Warren equates marriage to "liberty" (oh god, the amount of jokes that can come out of that), which was denied to the Lovings on the basis of race. Persuasive? I think not. I mean, you can make the argument, but you'll notice that not even Warren really tries.
The Equal Protection analysis is more to the point. It is worth re-stating that when we engage in Equal Protection analysis, we are looking not at the conduct engaged in (typically), but the people engaging in it. To use my favorite rhetorical device of assuming a ridiculous example, imagine someone wants to play hopscotch, but some town has a law in place that only blonde people (good for me) can play hopscotch on public property. Some firey red head then files suit saying the government is restricting her ability to engage in the god-given right to play hopscotch. The courts then have to find whether (a) hopscotch is a "right" and then whether (b) there is some basis (whether "rational" or of a more heightened variety depending on the class of person involved) that the government can rightly use to support its law. Note that the "rational basis" test is almost always a win for the government, Loving notwithstanding.
Currently the debate is about the institution of marriage, or the right to marry. It seems everyone in the various branches of the federal government is of the opinion that marriage is the right of all rights, second only to the right to commit sodomy. The issue then is whether marriage is universal to all citizens, and if so, if there still might be a reason to restrict it to certain peoples.
Buying into the premise then that marriage is a "right", we need to take the next step. The one side of the argument will say that "marriage" is a right not universal to all citizens, and therefore, you really don't need to get into an argument over why you're restricting it. The Rosies of the world say that everyone has the right and that as such, you can't deny it to anyone. The middle ground would be that it's universal, but there can be compelling reasons to deny it. This is where the courts are likely to find themselves. But once you do that, and if, you buy into it being a universal right, I think the argument for exclusion falls apart (I mean, we let convicted felons marry - assuming it's boy/girl). Then you get into this justification that only heteros "deserve" marriage; or that we must preserve the historical sanctity of marriage. Puh-leeze.
The buzz phrase now is "let the states decide", but that leaves out the fact that "civil union" is of limited value if it's only valid in the state of inception. Being married gives the pair quite significant property rights, and if they can be easily disregarded in another jurisdiction, you are indeed making gays second-class citizens.
There, I'm spent.