I'm not one who thinks the attorney general should be some sort of lone renegade within the administration, but he should feel empowered to aggressively push back against abuses of presidential power. Holder's history offers little evidence of that sort of temperament.
I think these are very legitimate concerns. The one thing I'd say in Holder's defense, though, is that the temperament he displayed during the Clinton administration may well have been in response to the, uh, unique set of circumstances at the Justice Department at the time--which, in Janet Reno, featured an attorney general who basically was a lone renegade within the administration and, in Louis Freeh, an FBI director who seemingly conspired against the administration. In other words, maybe Holder felt the need to be more of a company man than he would have otherwise given Reno and Freeh's chilly relationships with the White Housse. That doesn't necessarily excuse Holder's role in the Rich pardon, but it could explain it. And it could offer some reason for optimism about how he'd serve as AG under Obama.