One secret reason Petraeus had to resign

…CIA Director David Petraeus, as a senior civilian in the presidential chain of command should something go catastrophically wrong in Washington, violated special behavior codes for officials who might one day be forced to execute nuclear strikes.

In classified presidential emergency action documents, the CIA director is among the dozens, if not hundreds of officials who are listed as National Command Authority successors in the event that higher ranking officials are no longer able to do their jobs.

Because under certain circumstances he’d have ready access to the nuclear satchel, Petraeus was indoctrinated into the Personnel Reliability Program, which evaluates and monitors the lifestyle and behavior of Americans with access to nuclear command and control mechanisms. Adultery is not a minor sin under the PRP rules.