I can't figure out just WHY Oppenheimer wasn't gone after in a big way. Maybe Ike & Hover thought that curtailing his availability to the exact inside info was enough. Maybe they didn't have enough solid info to actually put him away, so refrained from stirring up the hornet's nest in a BIG way. Maybe, just maybe, the country's ( and media's ) mixed feelings about HUAC and the Rosenbergs had something to do with it. I wish I knew; heck, I wish somebody knew the real skinny, for sure. So much is blurry.