This is my favorite part of the oral argument in the same-sex marriage cases (from Lyle Denniston's analysis at SCOTUSblog):
The federal government’s view is that the Court should rule in favor of same-sex marriage, based upon the Fourteenth Amendment’s guarantee of legal equality. He [Solicitor General Verrilli] had no answer when Justice Kennedy asked him for the government’s views on whether gays should have a right to enter marriage, under the Fourteenth Amendment’s Due Process Clause, because marriage is a fundamental right. The government was not prepared to opine on that issue, Verrilli told Kennedy.
I like the subtle message sent here.
Among other reasons, there's a practical (though originalist-based) argument for preferring the equal protection clause over the due process clause. A problem with finding a fundamental right to marriage unmoored from the traditional understanding of marriage is that there is no obvious stopping point. If same-sex couples have a fundamental right to marriage, why not polygamists? Or indeed people who want to marry their brother, or their dog, or their piano? At some point the Court would have to say what is "really" a marriage and (critically) what is not. There is simply no way to do this on the basis of anything other than the judge's moral intuition. Like other arguments from moral intuition purporting to rest on the due process clause, the whole enterprise is corrosive of the rule of law. No one will think of it as anything but the Court making it up. (This concern has been raised by commentators generally sympathetic to same-sex marriage, for example here by Elizabeth Price Foley and here by Josh Blackman.)
But this concern has force only if one thinks of the case as being about marriage (the due process perspective) instead of being about discrimination (the equal protection perspective). Equal protection offers a more defensible grounding, and a more defensible stopping point. As I've argued, the key is describing sexual orientation discrimination as a form of caste legislation. (In modern doctrinal terms, to think of laws discriminating against people of same-sex sexual orientation as targeting a "suspect class" and thus requiring a "compelling" justification.) It seems fairly straightforward to say that sexual orientation — but not a preference for polygamy, or for other nontraditional versions of "marriage" — constitutes such a suspect class. Put another way, sexual orientation discrimination can be analogized to race discrimination (clearly proscribed by the Fourteenth Amendment) in a way that laws against other kinds of non-traditional marriage cannot. And that provides a stopping point that can be explained on legal grounds connected to the Amendment's original meaning.
Posted at 6:27 AM