"This has always, always been a problem for McCain: His strongest instinct, when confronted with any domestic-policy problem, is to find a black hat to pin the blame on and then punish them for it, rather than looking for the smartest possible solution." -- Ross Douthat

I think that's right. This is a major problem with McCain's foreign-policy thought as well, though at least that's an area where punishing bad guys sometimes is the smartest possible solution.