This article will analyze Operation OVERLORD in terms of the strategic and operational setting; examine campaign maneuvers, operational fires, and logistics; and conclude with a discussion of lines of operation as it applied in this situation.
Strategic Setting:
By the spring of 1944, Eisenhower's plan focused on the defeat of the German Army and its key industrial base. The strategic aims of the Allies were to " . . . enter the continent of Europe . . . and undertake operations aimed at the heart of Germany [Ruhr industrial base] and the destruction of her armed forces" (Clausewitz's "hub of all activity" from which power emanated). The strategic aims of Germany were to retain control of large territorial gains in the West and avoid a second front in Europe.
Strategic Centers of Gravity:
The strategic center of gravity of the allies was the massive strength of the combined coalition forces in terms of relatively undepleated air, ground, and naval combat power which could be concentrated on the European Continent, a force which was complemented by US war production capability which was fully capable of supporting the coalition effort. The strategic center of gravity of Germany was its sizeable mobile ground combat force which could, in theory, be quickly deployed and concentrated against any invading allied force.
Strategic Vulnerabilities of the Allies and Germany:
An Allied invasion faced a number of problems and potential strategic vulnerabilities. Logistics (availability of landing craft, war supplies, and troop buildup in Great Britain), the need to achieve near total air superiority, the containment of the German submarine offensive capability, the destruction of the French rail and road networks, major operations in North Africa and Italy and the timing for ANVIL were strategic issues and potential vulnerabilities which legitimately delayed the invasion, first until 1943, and ultimately until summer of 1944.
Operational Aims:
Germany was confronted with the difficult operational predicament of predicting precisely where the attack would come and how to best defend against it with some 53 divisions spread throughout France. Also, Rommel was keenly aware of the impact of allied air superiority (operational fires) on any defense plan. Both Rundstedt and Rommel were reasonably convinced that the attack would come at the Pas de Calais. It was the closet point to the British coast and nearer to key objectives such as the Rhine River and Ruhr industrial complex. Both commanders and Hitler agreed that the early hours of any invasion would be critical. However, there was serious disagreement on how to deploy reserve forces and when to commit them. Rommel understood air power and knew that reserves would have to be deployed forward to be effective. The problem was exacerbated by Hitler's unwillingness to make key decisions and his decision to deploy the best units on the Eastern front. Hitler also placed unrealistic confidence in his Atlantic Wall and perceived advantages which would be gained from the "V" weapons.
Command Relationships:
Commencing with the ARCADIA Conference (Germany-first strategy) and continuing between 1941 through early 1944 the Allies did extensive planning for a cross-channel attack (COSSAC) and refined the joint command relationships which culminated with Eisenhower's selection as Supreme Commander in 1944 of all joint forces. The resultant staff was fully integrated with allied officers and designed to avoid the pitfalls identified from lessons learned in WW I. Eisenhower in effect became a unified commander with a functionally organized command. The Deputy Commander, Air Chief Marshal Sir Arthur W. Tedder, was a veteran of the North Africa campaign and a strong proponent of combined operations. All allied Naval Forces were placed under the command of another British officer, Admiral Sir Bertram Ramsey. The US and British tactical air forces were combined and under the command of British Air Marshal Sir Trafford Leigh-Mallory. LTG Omar Bradley and General Sir Bernard Montgomery commanded US and British Army Groups respectively. This organizational structure resulted in the direct integration of the coalition forces and contributed significantly to their overall combat effectiveness.
Analysis:
Army Field Manual 100-5 recognizes five distinct forms of maneuver which a commander may employ against enemy forces. In deciding on a particular maneuver, the CINC should consider METT-T factors. Also, his statement of intent and concept of the operation should define how his operational fires will be used to support the particular maneuver. The five recognized forms of maneuver are: envelopment, turning movement, infiltration, penetration, and the frontal attack. Each was used successfully during OVERLORD.
The initial landings at Utah, Omaha, Gold, Juno and Sword Beaches comprised a frontal assault by two US and three Allied Infantry Divisions on an area between the Carentan Estuary and the Orne River and the east cost of the Cotentin Peninsula. The VII Corps landing at Utah beach on the peninsula was preceded by an airborne assault by the US 82nd and 101st Airborne Divisions behind enemy lines north of Carentan, an infiltration maneuver designed to confuse and disrupt German defenses by maneuvering against their rear elements.(note 1).
The plan called for a rapid advance by VII corps which would link up with the airborne units and secure the port of Cherbourg and the peninsula. US forces would also drive south and cut off the Brittany Peninsula. The German situation was hampered by an absent Rommel and a refusal by Hitler and his staff to acknowledge that Normandy was the main thrust of the allied invasion. Consequently, key reserves under OKW control were not released in time to respond effectively. During the ensuing six week period Hitler still refused to redeploy 15th Army units, contrary to advice of his ground commanders, continuing to believe that an attack would come at the Pas de Calais. This was a critical period during which the Allies carved out the beach head area where they would eventually pour in a million man force and conduct the breakout (note 2).
After experiencing tough German opposition such as that encountered at St. Lo, the frustrations of war in the hedgerows, and fearing the possibility of a potential stalemate similar to that of WW I, Bradley, with Eisenhower's blessings, formulated Operation COBRA which, like the unsuccessful British Operation GOODWOOD, was designed to achieve a breakout.
Operation COBRA involved a six division penetration by a concentrated Allied force across the St Lo to Periers highway. Following heavy carpet bombing along a three mile front, on July 25th three US infantry divisions punched a hole in the German lines after which three mechanized divisions exploited the breach.
This was precisely the text book course followed by VIII Corps when it turned West into Brittany while the XV Corps raced toward Argentan. However, critics now see the Brittany move as operationally flawed since the Breton ports ended up having little significance to the overall effort and the forces would have been better employed in the Eastern drive. Indeed this required the expenditure gasoline which later proved to be in short supply during Third Army's race to the Rhine.
Hitler's response to the breakout was to order von Kluge to launch a counterattack on August 6th across the narrow corridor from Mortain through Avranches to the sea to cut off the US troops racing south. The effect of the German counterattack was to commit the German 7th Army deep into Allied territory and create the Argentan-Falaise pocket.
At this point, Bradley and Montgomery recognized that an attack South by the British 21st Army Group in conjunction with a sweep north by Patton's XV Corps could result in a classic double envelopment which would sever the German 7th Army lines of communication.
Operational Fires:
As previously noted, operational fires also played a key role in the success of OVERLORD. FM 100-7 defines this as the application of firepower to achieve a decisive impact on the conduct of a campaign or major operation. Such fires are normally provided by assets other than those required for the routine support of tactical maneuver (Naval gunfire and Air assets). The use of such assets to destroy key bridges, roads and rail assets throughout France prior to D-Day severely hampered the ability of the Germans to maneuver in response to the invasion. Also, by June, 1944, the German Air Force had been virtually defeated, allowing the Allied Air Force to be used as a serious threat to any large scale vehicle and troop movements during day light hours.
Lines of Operation:
It is also instructive to examine the above described operations in terms of Jomini's theories about lines of operations. Jomini contended that all theaters have a base of operations (the lodgement area at Normandy and the modern concept of the COMMZ are examples) and that enemy strategic and decisive points (purists refuse to equate decisive points to centers of gravity, however the practical distinction is probably one of semantics) are attacked along lines of operations. According to FM 100-5, a force is employed on interior lines when its operations diverge from a central point and it is closer to separate enemy forces than they are to each other e.g. the Allied situation in the first days of the invasion. By doctrine, interior lines benefit the weaker force since it has more flexibility in terms of lateral movement. The six division breakout in Operation COBRA is a good example. Conversely, a force operates on exterior lines when its operations converge on an enemy force such as occurred when the Allies took advantage of the Mortain counter-attack and attempted to close the Falaise pocket.
In summary, the OVERLORD operation could have benefited from better operational planning. The failure to analyze key options and exploit fully certain operational advantages probably prolonged the war to some degree. While seemingly simple things such dealing with the hedgerow situation and giving more consideration as to which sector would best support Allied armor were missing from the plan, in balance OVERLORD must be viewed from an operation standpoint as one of history's greatest military achievements.
1. The drops did not go as smoothly as planned, once on the ground units were more disorganized than anticipated, and casualties were higher than expected (Clausewitz's friction at work). Nevertheless, the airborne drop was an operationally sound maneuver.
2. Initially, the lodgement area would have to hold a vast amount of logistical supplies. Initially, these supplies literally lined the beaches. After solving the logistical problems of actually marshaling and delivering the force .e.g. the landing craft problem, the next major logistical problem was to secure adequate ports to handle the flow of supplies and then insure that flow of supplies supported operational objectives.