Why did Hitler’s imperial dreams take Stalin by surprise?

The most extraordinary thing, still, about Operation Barbarossa is the complete surprise the Wehrmacht achieved. In the early hours of 22 June 1941 the largest invasion force in history, ultimately some three million men, struck at the Soviet Union on a front of nearly 2,000 miles. When Stalin was woken with the news, he wouldn’t believe it. It couldn’t be Hitler’s doing, he insisted; surely just sabre-rattling by Wehrmacht generals? Hours passed before he would accept his calamitous misjudgments and issue a general order to fight back by every means.

Hitler’s strategic challenge in the late 1930s had been essentially the same as the Kaiser’s in 1914: how to make war simultaneously on two fronts. The Kaiser, thanks to a theoretical plan conceived 20 years earlier by the chief of the Grosser Generalstab, Alfred von Schlieffen, ‘solved’ the problem by tactics inspired by the Battle of Cannae, in which Hannibal annihilated a superior Roman army by encirclement, and Napoleon’s ‘strategy of the central position’, designed to defeat two cooperating armies by concentrating force against one of them till it yielded, then turning to face the other. Schlieffen’s plan entailed a holding operation on the Russian front while sending the bulk of the imperial German army through neutral Belgium to encircle the French. Thereafter the victorious army would entrain for east Prussia to deal with the slower-mobilising Russians. With such brilliant officers as there were on the General Staff in 1914, what could possibly go wrong?

But this elevated battlefield tactics to the level of strategy. One of Hitler’s best field marshals, Albert Kesselring, said the Kaiser’s staff disdained ‘anything to do with oil which soiled the fingers and hampered the tactician and strategist in the free flight of his ideas’.