The Second World War saw the triumph of mobility, but also, what is often overlooked, a further exponential increase in logistical constraints, linked to the volume of personnel hired by the belligerents, the development of the number and performance of weapons systems and the increase in the number of elongations.

As regards mobility, it is certainly due to the systematisation of land motorisation, but it also lies in the use of airborne means. As early as 1940 in Holland, the Wehrmacht carried out the first large-scale airborne operations in history. This process will be resumed by the Allies in Normandy and during the operation Market garden. But at the same time, the limits of such a process implemented on a large scale were noted. The Arnhem operation ended in failure due to the impossibility of joining the airborne and ground troops on time.

Crete, although conquered, nevertheless became "the tomb of the German paratroopers". In Normandy, the dispersion of the dropped units considerably reduced their effectiveness. In addition, the loss rate of this type of operation was very high. On the other hand, the design of operations in difficult environments, jungle or mountain, illustrates that success always crowns units that have retained their mobility and rusticity: Marshal Slim's Burma campaign or the Italian campaign of the French Expeditionary Force, led by Marshal Juin. On another scale, this mobility factor was also the key to Leclerc's success during the raid on Koufra.

Concerning logistics, the campaign in Cyrenaica, marked by its incessant return trips between the Egyptian border and Tripolitania is enough to illustrate the tyranny imposed by the consumption of modern equipment in view of the elongations. The same problem justifies the choices made by the Allied High Command for the conquest of the Channel and North Sea ports in 1944, where the American difficulties of the autumn of the same year as the borders of Belgium and Luxembourg approached. The army, which manoeuvres as close as possible to its bases, benefits from a major asset.

In terms of general tactics, this conflict was characterised by the triumph of joint combat and modularity, with the German Kampfgruppen constituting a parallel to the introduction of groupings within the Allied divisions. This flexible structure allowed for the decentralisation of the combat, but in return required the creation of larger staffs as a result of the necessary coordination measures. The distinction between command and control is created here.

Finally, if not the emergence of a new level of manoeuvre, intermediate between the classic tactical and strategic levels, is formally taken into account: the operational level. This is induced on the one hand by the emergence of the notion of joint planning and conduct of operations in an air-land context and on the other hand by the notion of the "operational level".The theatre commander must hold all command responsibilities in his own hands.

The Allies applied it remarkably well in the European theatre in 1944-1945 with the creation of SHAEF 18while the Soviets, on another scale, implement it in the form of "fronts", an intermediate level between the STAVKA 19 and armies. Moreover, it is paradoxical to note that one of the reasons for the German failure stems, in part, from the failure to take this principle into account, whereas the notion of "operative art", deThe concept of "operative art", developed between the two world wars by the Soviets, was well known to German military leaders, who nevertheless remained very close to the concept in force in the 19th century.

This drift certainly finds part of its origin in the hypercentralisation of the high command due to the very nature of the regime and in the absence of real German doctrinal innovations: the Kriegsakademie trained excellent tactical "technicians", "professionals" in the use of weapons, not thinkers. It is obvious that the "young armoured school", illustrated by Guderian and Manstein, imposed itself against the advice of the military high hierarchy, thanks to the political support it was able to benefit from. In France at the end of the Second World War, the concept of the mobile group was back on the agenda in Indochina, where the expeditionary force was confronted with a ford.rilla that would gradually evolve into a more conventional war due to the rise in power of the enemy battle corps, in a particularly hostile environment, the jungle or the rice fields.

On the other hand, in Algeria, the French army had to review all its rules of use: confronted with an irregular conflict in both open and urban areas and having to control the population in a territory made up of French departments (this is not a war, but an "operation").The army has to square the terrain, secure it with watertight border checkpoints, reduce the number of gangs by means of vast operations and simultaneously destroy the rebel political and administrative organisation.

These two conflicts, especially in Algeria, saw the beginnings of aeromobility through the intensive use of helicopters, first of all in their function of medical evacuation and air transport. The context of this conflict gave rise to many differences of appreciation between the actors on the ground: the advocates of "psychological warfare", led by Colonel Lacheroy and a few other officers, gave priority to rallying the population by turning the methods of the rebellion against them. They opposed the partisans of the "all-military", such as Generals Challe and Vanuxem, who hoped, through major operations, to "break" the rebel bands and break the revolt.

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18 Supreme Headquarters of Allied Expiditionary Forces in Europe.

19 Soviet General Staff, the name of which dates back to the Tsarist era.