David Brooks, in his online conversation with Gail Collins, observes of the upcoming rally by Stephen Colbert and Jon Stewart:

By the way, I’m totally confused about what the political impact of Stewart-stock and Colbert-palooza will be. On the one hand, watching their shows I get the impression they are generally mainstream liberals. On the other hand I do think their shows are unintentionally conservative. Just as the show “60 Minutes” sends the collective message that political institutions are corrupt, so the Comedy Central shows send the message that politicians are buffoons. Both messages undermine faith in political action and public sector endeavor and so cut right against the intentions of their founders.

But normally their audiences are self-selected, largely liberal viewers who enjoy the collective experience of mocking conservatives. So they don’t really do damage to their “cause.” Their goal is more cultural than political: to reaffirm that they are cooler, smarter, and more clever than those dim-witted right-wingers.

How that comes off to the “public” — that is, a larger audience that is not in on the joke but rather the butt of the joke — is what has so many liberals nervous. The title of the event — the Rally to Restore Sanity — tells it all. Like Obama (but funnier), Colbert and Stewart are quite certain that Americans, after demonstrating sheer brilliance in 2008, are suffering from some mental affliction. If the comedians really wanted to restore sanity, they’d start with those on the left who are convinced that foreign money, Karl Rove, and Fox News are to blame for their party’s woes. But I don’t see that happening.