Krauthammer knocks it out of the park:

Al Gore's dramatic endorsement of Howard Dean catapults Dean to the status of prohibitive favorite because, according to conventional wisdom, it connects the outsider campaign to the ultimate insider. The insurgency gains access to the centers of party power -- the unions, ethnic constituencies and big donors close to Gore.

This is all very true. But the special power of this endorsement is less structural than symbolic. The story of this campaign is the energy and anger of the Democratic base. It is the reason an unknown and undistinguished former governor of Vermont is now the front-runner. He captured and then bottled the anger.

The anger appears odd, given that George W. Bush is fairly mild-mannered. He is no Richard Nixon. Democrats did not hate him in 2000. Yet many hate him now because of 2000, because they believe his entire presidency to be illegitimate.

Indeed.