Adolf Hitler failed to pay as much attention to bombing the enemy as he did to protection from enemy bombing, although he had promoted the development of a bomber force in the 1930s and understood that it was possible to use bombers for major strategic purposes. He told the OKL in 1939 that ruthless employment of the Luftwaffe against the heart of the British will to resist could and would follow when the moment was right; however, he quickly developed a lively scepticism toward strategic bombing, confirmed by the results of the Blitz. He frequently complained of the Luftwaffe's inability to damage industries sufficiently, saying, "The munitions industry cannot be interfered with effectively by air raids ... usually the prescribed targets are not hit".