June 1944: Allied invasion of Normandy

In coordination with Operation Bagration, undertaken by the USSR, the Allies invaded Normandy on 6 June 1944. The invasion of Normandy was launched from prepared sites on the south coast of Britain, with Allied landings in Normandy establishing beachheads and pushing inland. Once beachheads were secured, additional forces were brought over the English Channel. By August 1944, over 2 million Allied soldiers were deployed in France and had reopened operations against the Axis on the Western Front.

The plan for an invasion over the English Channel had existed since American entry into the war in December 1941. The USA and the USSR proposed an invasion of western Europe across the English Channel as soon as the USA entered the Second World War as a way of relieving pressure on the USSR. Britain, however, had opposed this plan because it feared that a direct attack on western Europe would result in a defeat reminiscent of the Battle of Dunkirk and the Battle of Le Havre. Britain and the USA came to a compromise in 1942, with Britain agreeing to an invasion of western Europe in 1944 at the latest in return for America agreeing to an invasion of North Africa. In 1944, Britain had to fulfill its promise and approved an invasion of northern France.

Allied success in the invasion of Normandy rested on an overwhelming advantage in manpower and equipment. The Allies achieved their initial beachheads through total air superiority and the assistance of naval bombardment. Once these beachheads were established, the Allies could send across a huge force to establish numerical superiority in northern France. By the end of July, over 1 million Allied troops were landed in northern France; by the end of August, this was over 2 million.

The invasion of Normandy opened up a third front against the Axis, in addition to the Eastern Front and the Italian Theater. The invasion forced the Axis to divert forces to France from other fronts, preventing the Axis from reinforcing the Eastern Front during Operation Bagration. The Allied pressure from the invasion, combined with the subsequent invasion of France’s Mediterranean coast on 15 August 1944, forced the outnumbered Axis armies to retreat back to Germany and Italy to shorten their defensive lines, essentially surrendering France to the Allies. This additional front in western Europe benefited the Allies, as another front forced the Axis to split their numerically inferior forces across multiple theaters, giving the Allies local superiority of forces in each theater.

France had served as a major submarine hub for the German navy and the main base for launching attacks against transatlantic shipping, particularly the Lend Lease supply convoys to Britain. The recapture of French naval bases by the Allies eliminated much of the German threat to Allied shipping, allowing for more Lend Lease supplies to reach Britain and the Western Front.

The invasion of Normandy, combined with the invasion of southern France in August 1944, resulted in the Allied liberation of France. The return of Charles de Gaulle’s Free French government to Metropolitan France involved the transfer of France’s extensive industry and natural resources, especially coal and steel, from Axis to Allied control. French industry and resources had been crucial to the Axis war effort and the Allied recapture of France further increased the disparity in the resources and industry available to war industry in the Axis versus the Allies.