On Friday night, Herman Cain was a fly and David Letterman was the spider cordially inviting Cain to "step into my parlor." Didn't Cain or any of his advisors see the potential for disaster in Cain appearing on Letterman's show? Didn't anybody say, "Herman, don't go in there! It's a trap!"? I desperately don't want to be seen as one of those just itching for clear proof that Herman Cain's candidacy is over. But it's hard to have watched Cain on Letterman and not come to the conclusion that neither Cain nor his advisors have sufficiently good judgment for him...