Just because David Petraeus has resigned as CIA director doesn't mean he shouldn't testify to Congress about the Libyan disaster. He was the one in the chain of command at the time, and whether still in office or not, he damn well ought to be questioned. Congress should NOT excuse him from testimony; whatever information he has is vital to understanding what happened. For Congress, this should be a hill to die on. This isn't to question the integrity of Petraeus (outside the marital realm); this is to get the information the public has the absolute right to know. Period.