▁since ▁three ▁of ▁the ▁review ers ▁held ▁the ▁same ▁ide ological ▁and ▁political ▁views ▁and ▁two ▁of ▁them ▁were ▁from ▁the ▁same ▁Washington ▁DC ▁think ▁tank . ▁ ▁He ▁noted ▁that ▁the ▁C IA ▁prevent ed ▁him ▁from ▁re le asing ▁the ▁names ▁of ▁the ▁outside ▁review ers ▁of ▁the ▁ 2 0 1 1 ▁Iran ▁estimate . ▁ ▁Several ▁high ▁U . S . ▁military ▁and ▁intelligence ▁officials ▁have ▁stated ▁that ▁the ▁effects ▁of ▁an ▁Isra eli ▁attack ▁on ▁Iran ' s ▁nuclear ▁facilities ▁would ▁not ▁be ▁prevent ive . ▁ ▁Def ense ▁Secretary ▁Leon ▁E . ▁Pan etta ▁said ▁in ▁December ▁ 2 0 1 1 , ▁and ▁L t . ▁Gen . ▁James ▁R . ▁Cla pper , ▁director ▁of ▁National ▁Int elligence , ▁said ▁in ▁February ▁ 2 0 1 2 ▁that ▁an ▁Isra eli ▁attack ▁would ▁only ▁delay ▁Iran ' s ▁program ▁by ▁one ▁or ▁two ▁years . ▁ ▁General ▁Michael ▁V . ▁Hay den , ▁former ▁C IA ▁Director , ▁said ▁in ▁January ▁ 2 0 1 2 ▁that ▁Israel ▁was ▁not ▁able ▁to ▁inf lict ▁significant ▁damage ▁on ▁Iran ' s ▁nuclear ▁sites . ▁ ▁He ▁said , ▁" They ▁only ▁have ▁the ▁ability ▁to ▁make ▁this ▁worse ." ▁In ▁February ▁ 2 0 1 2 , ▁Admir al ▁William ▁J . ▁Fall on , ▁who ▁retired ▁in ▁ 2 0 0 8 ▁as ▁head ▁of ▁U . S . ▁Central ▁Command , ▁said , ▁" No ▁one ▁that ▁I ' m ▁aware ▁of ▁thinks ▁that