Actually he has failed to really bash Bush, IMO. He's had one skit that I can really remeber that was titled "Black Bush" that showed what Bush would have said had he been black, it was pretty funny I thought. The other time I can remeber that he brought Bush up was when he did a skit that was 2 minutes long that took him like all the time to get on stage and when he did he said, "Wanna know what I think of Bush? Wanna know what I think of the war in Iraq?" and the buzzer went off to end the skit.
The highlight of the skit was the UN questioning.
"The UN doesn't like what I'm doing? Then they should sanction me. Sanction me with their army. Oh, they don't have an army? Then they need to Shut The *$%$ up. You don't have no army? Then Shut the $#&# up!"
He earned my respect by spoofing the mitsubishi eclipse ad with the girl dancing (err, convulsing) in the passenger seat.
Actually, Chappelle has been really smart. He's stayed out of specific politics. Sure he makes political sketches, but usually they are harmless and intelligent. What's imporant though, is that he refrains from making political comments outside of his comedy. Therefor he prevents the alienation of some of his viewers. He is a comedic genius.