That said, I think I would have taken the half-loaf of civil unions if I were the SJC. I've admitted before that the country may not be ready for gay marriage, and that endowing committed couples with all the attendant rights of marriage (without calling it such) might be the best we can get without a big battle over amendments. Ideally, as we've discussed, the solution, improbable as it may be, is to make the government the disinterested registrar of all unions (so that any couple can have the benefits regarding probate, custody, taxes, etc.) and make marriage a purely religious institution. Thus, if your church says gays can marry, bully for you. If the church down the street says no, tough shit; find yourself another church.
As for Sullivan, I love his work, but I don't take his stuff awfully seriously on the subject, especially when he buys into this kind of thinking.
Anyway, politics is the art of the possible. Jurisprudence need not concern itself with the possible, only with the legal. Thus do we occasionally have huge fights over busing, abortion, and -- coming soon -- gay marriage. I realize that, and I regret the acrimony ahead of time. But those who say that the legislature should handle the issue didn't seem to be forthcoming with any legislative accomodation until (as in Vermont and Massachusetts) the courts forced them to. As we saw with Lawrence v. Texas, the conservatives all thought the law was anachronistic and should be repealed by the legislature, but not overturned by the court. The question is, how long are you willing to give the legislature?