Will McCain run as a third party candidate in 2008?

Mickey Kaus over at Slate argues that McCain could win as a third party candidate.McCain couldn't get the Republican nomination,he couldn't get the Democratic nomination,and his base of support is somewhat bigger than the Washington D.C. establishment.It's difficult to think of how he could get enough support to overwhelm the two major parties.After his fine performance restricting free speech he could get on the board of directors of the Washington Post as a token Republican.