Stephen Biddle has worked in groups with what general who resigned from the Central Intelligence Agency in 2012?
Stephen Biddle:  He also has worked in groups under Generals Stanley McChrystal and David Petraeus forming U.S. counter-insurgency policy. David Petraeus:  He served as Director of the Central Intelligence Agency from September 6, 2011, until his resignation on November 9, 2012.
David Petraeus