 One theory is that Von Rundstedt and Hitler agreed to conserve the armour for "Fall Rot" ("Case Red"), an operation to the south.It is possible that the Luftwaffe's closer ties than the army's to the Nazi Party contributed to Hitler's approval of Göring's request.Another theory—which few historians have given credence—is that Hitler was still trying to establish diplomatic peace with Britain before Operation Barbarossa (the invasion of the Soviet Union).