Kennedy took responsibility for the Bay of Pigs fiasco, which hadn't really been his baby. Didn't do him any harm. LBJ made no admissions of fault or apology for the escalation of Iraq...sorry, Vietnam, and he was despised. Carter really didn't have many problems because of that interview. I think the hostage situation and the failed rescue attempt (for which he did take responsibility a la Kennedy) and the continued stagflation from Nixon and Ford's terms are what did it.

I think you are right that there are dangers in apologizing. But I think the American people want to hear from their electeds that they feel duped, they were wrong and they are pissed because Bush fooled them the same way he fooled the American people and the time has come to set things right.

Hillary has been an apologist for Bush's Iraq quagmire for so long I think she really owes those of us she is supposed to be supporting (that's me...my vote went to electing her in the first place) some explanation and apology for her being an Iraq war apologist.