Although it was an awesome military operation, and a moment of acute symbolism as the liberation of Europe began, D-day itself was not a great battle by the bloody standards of modern war.At Omaha Beach, the Americans lost 2,220 casualties, mainly from the Rangers and the First Division. At Utah Beach, where the terrain was less hostile and the defenders more demoralized, the American Fourth Division suffered 187 casualties. In contrast, just 17 days after D-day, Hitler's Army Group Center on the eastern front lost over 50,000 men at Vitebsk alone.The point about D-day was that it was not a single event, but part of a long campaign. With hindsight and a sense of history, we might even say that, the battle of Arnhem -- three months later in September, 1944 -- was more significant.Arnhem was a battle that concerned far more than the defeat of Germany: It was about the post-war map of Europe. The goal was for the British and American armies to use an airborne landing to cross the Rhine and get into the heart of Germany before winter set in. With Germany's industrial heartland under their guns, the Anglo-Americans could occupy Germany before the Russians did.This was the nightmare that Churchill had dreaded in the early summer of 1944, when the Soviet armies were racing into Poland and the Balkans. "The Russians are drunk with victory and there is no length to which they may not go," he had written to his foreign secretary, Anthony Eden.To forestall too sweeping a Russian occupation, the British pressed -- not for the last time -- for a swift invasion of Germany in the hope of reaching Berlin before the Soviet armies. They almost made it. But at Arnhem, they failed.Defeat at Arnhem condemned the Allies to a winter before the German Siegfried line. The Rhine was not crossed until March, 1945, when the Red Army was at the gates of Berlin. At that moment, the hitherto barely foreseen results of the war crystallized.Churchill then flew to Moscow, in the hope that the traditional diplomacy of realism could secure what the airborne attack had failed to win. At 10 P.M. on Oct. 9, Churchill met Stalin and they carved up the map of post-war Europe together."How would it do for you to have 90 percent predominance in Rumania, for us to have 90 percent of the say in Greece, and go 50-50 about Yugoslavia?" was how Churchill recalled his offer in his memoirs. He sketched out the figures on a sheet of paper, adding 50-50 for Hungary, and 75-25 in Bulgaria (in Stalin's favor). Stalin "took his blue pencil and made a large tick upon it, and passed it back to us."The famous sheet of paper contained no reference to Germany, Czechoslovakia or Poland, the country for which Britain had gone to war, but which Churchill now considered a hopeless cause.Just before he left for the Yalta conference in February 1945, with the British and American armies still stuck on the wrong side of the Rhine, Churchill confided to his personal secretary: "Make no mistake, all the Balkans, except Greece, are going to be Bolshevized, and there is nothing I can do to prevent it. There is nothing I can do for Poland either."D-day was the turning-point at which history failed to turn. The battle of Arnhem was the moment the long post-war future was defined.