The single-scope background investigation for a top-secret clearance is pretty exhaustive..
NYT indicates that Manning was pretty openly gay, emotionally frustrated and combative... Also, he was fired once from a civilian job because of personality issues, and he got two reprimands — Article 15’s, in Army-speak — for misconduct, including “assaulting an officer.”
It’s hard to imagine that even the most liberal of background clearances wouldn’t have thrown a couple of red flags up when investigating a kid like Manning.
Trying real hard to maintain the maxim that what can be explained by stupidity should never be attributed to malice.
