The Daily Show is untouchable at this point. And I wouldn't say it's even necessarily a liberal show. Stewart has guests from all over the place, including a conservative today who has a book out about how direct mail and third-party media outlets influenced a conservative shift in the nation's political landscape. He also has both John McCain and Joe Lieberman on the show regularly. He has guests from all sides. He rips on Bush more because 1) he's the President, so there's naturally more material, and 2) he's Bush, so there's naturally more material. And the thing about the Daily Show is that it's popularity is so unquestioned that there's nothing anyone can do to bring it down. Think about it: news articles usually mention Stewart in the same category as Leno, Letterman, and Conan O'Brien, which isn't that impressive until you consider that Stewart's show is on cable (oh yeah, and The Daily Show is easily the best of any of those). It's like South Park and Chappelle's Show; not going anywhere for a while.
"I don't care if the Yankees are playing a team consisting of Saddam Hussein, Hitler, and Josef Stalin; I still want them to lose." -My Uncle