The constant fighting never allowed Hitler to build up a reserve large enough to regain the upper hand in the east. Employing the peculiar rippling effect that marked its offensives, the Red Army, thwarted in one place, had shifted to others. For the first time in the war it had the full strategic initiative, and it grasped it jealously without regard for economy of effort, tactical sophistication, or the danger of overreaching itself. The failure of "Zitadel" doomed the Germans to the loss of operational initiative on the Eastern Front without any hope of regaining it, although Hitler seems to have been unaware or unwilling to recognizing this reality. The terrible losses in manpower that the Germans suffered in July and August were ultimately fatal and left the armies of Army Group South and Centre too weak to do anything but delay the inevitable. Operation Polkovodets Rumyantsev marked the first time in the war that the Germans were not able to defeat a major Soviet offensive during the summer months and regain their lost ground and the strategic initiative.