The two cases ask the same basic question: Does the U.S. Constitution require a state (Proposition 8 case) or the national government (DOMA case) to change the definition of marriage to include same-sex couples?
To answer this question, the court would have to answer others. First, is there anything in the text of the Fifth or 14th Amendments that could plausibly read as a mandate to redefine marriage? (Taking a clause out of context to use as a slogan does not count.) Second, when the Fifth (1791) and 14th (1868) Amendments were ratified, could they possibly have been understood to require such a result?
Much of the chatter about the cases is about how the court will find a technicality to prevent ruling on the cases. It’s not clear whether that’s just an attempt to tamp down expectations by the pro-redefinition advocates who may recognize that the legal arguments are an overreach.
If, however, the court is to address the underlying question in the case, more than the cultural understanding of marriage (as crucial is that is) is at stake.
If we are indeed, governed by a written constitution, then the court’s answer (or even avoiding an answer) to these questions is important.
The answers are actually pretty easy. The Constitution allows the states plenary power over domestic relations and allows Congress power to determine what terms used in federal law mean. The Constitution does not codify the mores of the sexual revolution. It does not establish a super-legislature to censor the laws enacted in the normal political process.
That’s the bottom line.