Why was D-Day necessary?
What was, in 1944, the strategic situation in the European theater?
The strategic situation had already for some time forced Germany onto the defense. As often happens in history, the tyrants and conquerors are victims of their own greed and the Reich of Hitler in 1943 had conquered more territories than how much it could realistically control. Considering that the Allies had control of the sea since the beginning of the war, it is easy to comprehend how irrational it was to presume to defend a territory so vast and so exposed to amphibious actions.
The strong points of the entire German military apparatus were the mobility and rapidity of positioning, tactics that had determined the success of the Blitzkrieg and could have permitted the control of an empire. Instead all the materials and the research effort aimed at heavier armored means, but also slower and more costly like the tanks Tiger, Panther, Elephant, which gave the illusion of invincibility.
Hitler, after the enormous defeat of the campaign in Russia, the surrender at Stalingrad and the failed offensive Kursk, seemed to look for refuge in the idea that the fortifications and a defensive war could offer a solution. Enormous and costly works of fortification began in all of Europe, especially along northern coasts of France.
The war industry began to have difficulty with the supplying of raw materials. The war effort active on diverse fronts forced greater compromises in the quality and quantity of the weapons. Fuel, one of the primary goods, in the continuation of the war assumed a greater and greater importance. One of the major supply sources on the continent was the zone of oil wells of Ploesti in Romania, ever more within the reach of the Soviet forces and the raids of Allied bombardiers.
“He who wants to defend everything defends nothing”
Frederick the Great
For the Allies continuous progress was made in North Africa, liberated from the presence of the Axis at the end of spring in 1943, and in Italy, with the disembarkation in Sicily in July of 1943 (Operation “Husky”), that would bring about in almost a year the liberation of Rome June 5, 1944. No other open fronts existed in the European theater and the necessity of engaging the Axis brought about the approval of Operation Overlord in Normandy. A decision that had already been made for some time.
The industrial production of the US had reached levels unattainable for the Axis and was destined still to increase. The flow of reinforcements toward the United Kingdom and the Soviet Union could have been considered secure by then and fed the confrontation. The invasion of Normandy would also be an encounter between different industrial systems, between the quantity and trustworthiness of the weapons and materials of the Allied forces and the quality of the arms of the Reich.
For the Soviets the Great Patriotic War had frightening human and material costs. Russia had been the only European power to sustain the continuous pressure of the Axis for the greater part of the conflict. In 1943 the strategic situation improved, Stalingrad had fallen and Kursk had given a hard blow to the Axis armies putting them on the defensive, but the Axis, mostly German forces, sustained an ever strenuous defense and were not yet on the edge of collapse, despite the losses. Stalin in the course of the years asked with constantly greater insistence that a new front in Europe be opened; and for the Allies the fear became sharper that if they were not capable of giving an adequate response to the strategic necessities of Stalin, the Soviet Union would have been forced to find a political compromise with the Axis. This scenario is plausible considering that the Soviet Union and Germany had already made advantageous bilateral diplomatic agreements like the Ribbentrop-Molotov Pact of 1939, that had resulted in the partitioning of Poland. It is a suggestive scenario also because it hypothesizes the verification of exactly what happened in World War I, when in 1918 Russia signed a unilateral peace and the German troops redirected themselves onto the western front.