Orin Kerr has a few notes on a recent Antonin Scalia lecture:

Scalia then suggested that our faith in judges today is similar to our faith in experts decades ago. We expect judges to have answers to the great moral questions of the day. The trouble is that judges are not moral experts; they are just lawyers. Judges can dress up moral judgments in a legal opinion in a way that seems very impressive. The form of a legal opinion can create an illusion of expertise in the question (this is my language, not Scalia's).

But in fact judges have no greater insights into moral questions than anyone else. Scalia went on to discuss some of the provisions of the European Union human rights laws, which task judges with enforcing broad moral standards. The difficulty with this approach, Scalia suggested, is that it presupposes that judges have special insight into morality. Because judges do not have any special insights into such questions, it is better to leave them to the democratic process. Scalia then went on to discuss the benefits of an originalist approach to constitutional interpretation; among those benefits was that it did not embroil judges in all sorts of moral questions that they had no ability to answer.

This seems intuitively wrong, but it's hard to express why. For one—and I think Cass Sunstein has made this point well—judicial "activism," as it is usually understood, tends to follow popular opinion. Civil rights—including non-discrimination—didn't become a constitutional norm until long after the public largely deemed discrimination wrong. Ditto with gay marriage—you might say that only a minority supports gay marriage, depending on your polls, but it's a pretty hefty minority. If Sunstein is right and this is historically accurate, then activist judges ruling on moral questions aren't relying solely on their own expertise, but following to some extent the "wisdom of the crowds". I think.