From Bob Novak:
Powell, Hagel and lesser-known Obamacons harbor no animosity toward McCain. Nor do they show much affection for the rigidly liberal Obama. The Obamacon syndrome is based on hostility to Bush and his administration and on revulsion over today's Republican Party (italics mine). The danger for McCain is that desire for a therapeutic electoral bloodbath could get out of control.
Some Republicans are keen to emphasize hostility toward Bush while ignoring the "revulsion" over today's Republican party. Coming from a conservative and long-time Republican, revulsion is a very strong word, but it's the right word. What is happening now isn't simply about Iraq or Bush's intransigent leadership style. Many independents and moderate Republicans, and, notably, some genuine conservatives, are deeply revolted by the culture of arrogant chest-thumping, the dishonest smear politics, the pitchfork and lantern religiosity, and the constant appeals to racism and xenophobia that are the nourishments of today's party base.