I think you're judging the man too harshly. From what I recall, he wasn't credulous -- "I'm not reading this bullshit." If he was merely a passive tool Cheney wouldn't have poked him in the chest while telling him that he could "afford to lose a few points." There comes a point when the rest of ones team wants to go the other way so badly that saying, "This is a mistake." just sounds like, "I'm a traitor." This administration has been especially apt to hear internal criticism that way to boot.