washington u.s. defense secretary ashton carter decide impose punishment david petraeus former u.s. military commander cia director admit share classify information mistress accord letter see reuters short letter send stephen hedger assistant secretary defense legislative affairs decision line army review petraeus resign head cia 2012 reveal affair biographer army reserve officer paula broadwell plead guilty mishandle classify information court document sign petraeus prosecutors say 2011 petraeus illegally give broadwell access official binders april retire four-star general sentence two years probation fin 100,000 spar prison time plead guilty mishandle classify information pentagon could seek reprimand petraeus military law hedger letter address senate arm service committee chairman senator john mccain senator jack reed recently ask carter take action pentagon decline comment letter petraeus counter-insurgency expert princeton university doctorate serve top u.s. commander war iraq afghanistan consider possible vice presidential presidential candidate know black book binders petraeus share broadwell contain classify information include identities covert officer code word information war strategy intelligence capabilities diplomatic talk information high-level white house national security council meet accord court record petraeus serve chairman private equity firm kohlberg kravis roberts captive economic geopolitical think tank kkr global institute accord website retire general ex-cia chief david petraeus receive punishment