I think that the debate about turning points, illustrates one thing, and that is the difficulty in defining what is actually meant by 'turning point' i.e whether it is a shift in momentum, initiative or just the point of no return. Manstein believed that up to 1944, the war, notably on the eastern front, could be brought to a conclusion favourable to Germany, whether a stalement, or the achievement of conditions conduicive to a negotiated peace(the attainment of strategic victory given the circumstances) to allow the return to a 'one front' war. The victory of Tannebaum in the first world war is a good example, whilst not ending the war on the Russian front, the victory allowed Hindeburg to significantly reduce the demands and activity on the Russian front allowing the Western fronts to receive pre-eminence on a greater scale. If the offensive in 1918 had succeeded then Tannebaum would have rightly been in contention for a turning point of the first world war, it halted the wound opened by the entry of Russia into the war before it became terminal. Whilst Stalingrad was a very public indication of the death of German aspirations and ability to prosecute the war on the Eastern front to a successful conclusion, the initial goals of Germany were consigned to failure long before Stalingrad. The confidence which had been built up since the successful conclusion of the battle of France had evaporated at the walls of Moscow, the goal of achieving a total military victory of the Red Army had been supplanted consciously and unconsciously in the German high command before Stalingrad. The choices left open were to obtain a stalemated front, in order to concentrate on the west, or to obtain a negotiated peace on favourable terms, certainly after Stalingrad the prospect of obtaining favourable terms decreased dramatically, and Manstein's counter-offensive with army group Don was indeed only a delaying action with no influence over regaining initiative, merely a rear guard action to partially repair the situation. However by committing the last significant accumalation of German offensive reserves at Citadel, a last bridge was crossed, to risk one more roll of the die in the hope a tactical and military victory would allow for 1/a gain of initiative or 2/ the attaining of favorable conditions for a negotiated peace(Manstein also commented that another hope was to exhaust russian reserves in that sector). The generals who opposed citadel made the point that by committing these reserves, the chance to stabilise the Russian front would be lost, thus without Citadel one front could be stabilised in order to concentrate on the other, in the hope of bringing a successful conclusion to one. After Citadel, the Germans had neither of these options, instead presiding over an increasingly unstable Russian front and finding no reserves for offensives, small scale or otherwise, essentially the same problems existent after the battle of the bulge.