Erick Erickson writes brutally about Herman Cain's handling of his skeleton/closet eruption: "If I were allowed to use the word retarded these days, I’d use it to describe the Herman Cain campaign these days." The context here is revealed a few items later: Erickson has an exclusive interview with Rick Perry.
This is what I was trying to suggest on Monday. The incentives for conservatives to defend Cain are functions of their hopes for Cain to be the GOP's presidential candidate. Compare that to the incentives they had in 1991, defending Clarence Thomas: If they let him down, a black SCOTUS nominee who could serve for decades would be denied a seat. In 1998, if Democrats let Bill Clinton down, he'd have become the second president to resign in disgrace.
If Cain goes down then... well, conservatives have to rally behind someone else. None of their options are perfect -- if they were, there never would have been a Cain surge. Cain has a reservoir of goodwill to draw on, largely because the base likes him, partly because the base really, deeply despises the media. But there are forces in the conservative punditocracy and activist class who like other candidates. Cain's challenging their sympathy with stuff like Mark Block's baseless, retracted accusation that the Perry campaign was behind the Politico story. This, as much as any detail that emerges from the story, is what can sink Cain.