Every one of these people is too arrogant to take the fall willingly. The question really is: How much do they fear Barack Obama? So far, from what I've seen, the punk is incapable of inflicting damage the way Bubba was. He's not been around long enough to develop a cadre of thug henchmen. Mayhap this is why he's currying favor with AQ in Libya: Protection.
Holder, on the other hand, has no such leverage. He's toast, and he knows it but looks to be in denial.
Holder is playing cover up. Melson did not resign as some in the media are now reporting he was reassigned.