Matt on the weak-sauce that is "It's only symbolic" argument:

People who are upset about a politician doing something they don't like that's essentially symbolic in nature -- like the selection of Rick Warren -- often have difficulty articulating to skeptics exactly what the nature of the problem is. Simply digging up more and more quotes of the offending person's offending activities doesn't answer the reply "so what? it's just symbolism..."

A brief point to make is that it's very easy for a person who isn't part of the minority group that's being symbolically dissed to dismiss someone else's concerns as merely symbolic and not that big a deal. But it's worth considering how much public policy acts consistently to reaffirm the symbolic commitments of majority groups. If Barack Obama were proposing to eliminate Christmas as a national holiday and end the White House Easter Egg Hunt, nobody would be surprised to see people get very upset even though the concrete stakes would be low.

Heh, when its not your neck getting stepped on, it's "symbolic." Here's Ezra advancing the ball:

Warren is not a symbolic figure. He's a religious leader who mobilizes his flock and leverages his public influence in order to affect electoral outcomes. The most prominent example was the Proposition 8 ballot initiative -- as opposed to, say, the Proposition 8 symbolic logo design contest -- in California. Warren used his power and prestige instrumentally, not symbolically. And Obama is giving him more power, and more prestige, which he will, quite assuredly, deploy in an instrumental fashion.

Meanwhile, I'd also note that the people deriding concerns about Warren as "symbolic" are the same people who were dancing in the streets when Obama won the election. When the symbolism mattered to them, they weren't spending a lot of time noting that Obama's basket of policies was really pretty standard for a Democratic candidate and so people shouldn't get exercised over the symbolism embedded in his victory.