Earlier volumes have led us to the point where the aggressors, both in Europe and Asia, had been driven to the defensive. Stalingrad in February 1943 marked the turn of the tide in Russia. By May all German and Italian forces in the African continent had been killed or captured. The American victories in the Coral Sea and at Midway Island a year before had stopped Japanese expansion in the Pacific Ocean. Australia and New Zealand were freed from the threat of invasion. Henceforward in Europe the Axis must expect and await the Anglo-American assault which had so long been purposed. The tremendous armies of the United States were growing in strength and quality with every month that passed. But the Western Allies could never strike home at Hitler's Europe, and thus bring the war to a decisive end, unless another favourable change came to pass. Anglo-American "maritime power," a modern term expressing the combined strength of naval and air forces properly woven together, became supreme on and under the surface of the seas and the oceans during 1943. It was not until April and May that the U-boats were beaten and the mastery of the life-lines across the Atlantic was finally won. Without this no amphibious operations on the enormous scale required to liberate Europe would have been possible. Soviet Russia would have been left to face Hitler's whole remaining strength while most of Europe lay in his grip.
-Winston Churchill, Closing The Ring