After gaining a foothold on what German Field Marshal Erwin Rommel called the "longest day," the Allied march inland commenced following D-Day.

Unfortunately for the Allies, during 19-20 June a force 6-7 storm blew out of the northwest and severely damaged Mulberry A in the American sector. It also sank well over 100 small craft and drove many more ashore, bringing to a halt the discharge of supplies. Vital ammunition stocks had to be flown in. Mulberry A was abandoned, but a strengthened Mulberry B provided supplies to both armies until the end of the war.

The Allies put ashore 75,215 British and Canadian troops and 57,500 U.S. forces on D day and 1 million men within a month. Eventually, the United States committed 60 divisions to the battle for the Continent. The British and Canadians never had more than 20, and as the disparity grew, so too did U.S. influence over military and political strategy. Churchill was understandably insistent that Montgomery exercise prudence and not sacrifice his men needlessly, which would reduce British influence even further.

The Allied ground offensive, meanwhile, proceeded more slowly than expected. Hitler ordered his armies to fight for every inch of ground rather than withdraw along phase lines as his generals wanted. This decision by Hitler at first delayed the Allied timetable. However, it also greatly accelerated the ultimate defeat and ensured that it would be costly. Complete Allied air superiority devastated the Germans by day and forced them to move largely at night. The French Resistance also played an important role, providing the invading Allied forces with intelligence information and impeding German resupply efforts through sabotage and the destruction of rolling stock and bridges.

The Normandy countryside proved ideal defensive terrain. Over the centuries, the dividing lines between individual fields had been allowed to grow up into tangled hedgerows. This bocage resisted passage and slowed the Allied advance to a crawl. On June 17 and 18, the Germans blocked Montgomery's efforts to take the city of Caen. Major General J. Lawton Collins's U.S. VII Corps had more success on the Allied right, gradually pushing across the base of the Cotentin Peninsula. On 18 June, it turned north to liberate the important port of Cherbourg, while the remainder of Bradley's army maintained an aggressive defense. Cherbourg fell on 27 June, but its German defenders destroyed the harbor facilities, and it would take U.S. engineers under Major General Lucius Clay six weeks to get the harbor facilities back in operation.

Not until Operation COBRA on 25-31 July were the Allies able to break out. Bradley's U.S. First Army forced the German line west of Saint-Lo, and Collins's VII Corps made the main effort. All northern France was open for the highly mechanized Allied units to maneuver. On 15 August, Allied forces also came ashore on the French Mediterranean coast in Operation DRAGOON. The German defenders were now in full retreat, but it remained to be seen if the Allies could maintain their fast-lengthening supply lines and end the war in the west before the Germans had a chance to recover.

Spencer C. Tucker

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Citations:

Ambrose, Stephen E. D-Day: June 6, 1944: The Climactic Battle of World War II. New York: Simon and Schuster, 1994.

Blair, Clay. Ridgway's Paratroopers: The American Airborne in World War II. Garden City, NY: Dial Press, 1985.

D'Este, Carlo. Decision in Normandy. New York: E. P. Dutton, 1983.

Hartcup, Guy. Code Name Mulberry: The Planning, Building and Operation of the Normandy Harbours. London: David and Charles, 1977.

Hastings, Max. OVERLORD: D-Day, June 6, 1944. New York: Simon and Schuster, 1984.

Keegan, John. Six Armies in Normandy: From D-Day to the Liberation of Paris, June 6th-August 25th, 1944. New York: Viking Press, 1982.

Lewis, Adrian R. Omaha Beach: A Flawed Victory. Chapel Hill: University of North Carolina Press, 2001.

Masterman, J. C. The Double-Cross System in the War of 1939-1945. New Haven, CT: Yale University Press, 1972.

Mitcham, Samuel W., Jr. Rommel's Last Battle: The Desert Fox in the Normandy Campaign. New York: Stein and Day, 1983.

Schofield, B. B. Operation NEPTUNE. London: Ian Allan, 1974.