Tom Clancy's novel RedStorm Rising, also has a very special resonance with many military readers who entered the service in the 1980s. This work of fiction, published in 1986, is a very realistic account of a confrontation between NATO and the Warsaw Pact on European soil and in the North Atlantic.

Time has passed. The fall of the Berlin Wall and the geopolitical turbulence generated by the end of the Cold War have drawn the attention of strategists and war practitioners to horizons other than those of the Fulda Gap, while Western forces have been engaged in sustained stabilization and counter-insurgency operations. The return of power logics and inter-state competition, observed over the last ten years or so, seems to make armed confrontation in Europe or at the gates of Europe possible, if not probable. The prospect of a so-called "high-intensity" conflict has therefore given rise in recent years to major rethinking of a political-military, capability and doctrinal nature, particularly on the other side of the Atlantic. The authors of the 2017 Strategic Review thus recall that the political ambitions and sovereignty objectives that France has set for itself must result in a strategy, a doctrine for the use of armed forces and combat capabilities to be maintained or developed. The determination of the levels and processes of coordination and integration necessary for the global commitment of all the resources required for the preparation and implementation of a strategy for the use of the armed forces and the combat capabilities to be maintained or developed.The determination of the levels and processes of coordination and integration necessary for the global commitment of all the resources required for the preparation and conduct of the most demanding types of engagement, referred to as "high-intensity" operations, is also a vital imperative in this context[1].

1] However, the re-appropriation of a capacity to reason "high-intensity" warfare comes up against a certain ambiguity, both conceptually and in terms of capabilities. Literally, intensity refers to a degree of tension, force or activity of a thing, quality or power. We speak of the intensity of cold, of a sound, magnetic or electrical intensity. The term thus implies the objective expression of the numerical value of a quantity. However, war and violence lend themselves to

It is difficult to quantify and therefore to classify a typology whose intensity can be a discriminating parameter.

The purpose of this document is to initiate a reflection intended to feed into the work currently being carried out in the field of preparing for the future. It therefore aims to clarify notions that will help to better define what a "high intensity conflict" is or is not. Rather than the overly vague and restrictive notion of a "high-intensity operation", it is proposed here touse the notion of a major intervention, which is more structured interms of the use of forces and the capabilities to be held in such a framework.

Ambiguity and limits of the concepts governing the notion of intensity

High intensity" is often abusively associated with the notion of total war ("absoluter Krieg"), conceptualized by Clausewitz[2]. 2] This term describes an armed conflict that is not limited to the achievement of military objectives, but involves the mobilization of all available resources of the state and society. This concept is part of a logic of radicalization of the duel between two competitors and leads, in theory, the politician to commit all the forces at his disposal to destroy the totality of an adversary's capabilities. This notion implies the destruction, or at least the neutralisation, of civilian as well as military objectives. It imposes a centralized conduct of warfare at the highest level of the state. Finally, it implies total control of public opinion by means of advanced and targeted operations of influence, in order to ensure the support of all sectors of the population. It is therefore a concept that highlights the vital interests of a nation as much as unlimited coercive actions applied in all fields of confrontation (military, economic, diplomatic and ideological) for all belligerents. As the Prussian theorist points out, this model of conflict remains theoretical and is always limited in practice by factors such as the intervention of other states, the evolution of conflict situations and political calculations, mainly related to the conditions for future peace. Absolute war is therefore an interesting conceptual framework, but one to which no case ever fully applies.

The end of the Cold War also brings to light the notions of symmetry, asymmetry and asymmetry, which make it possible to characterize an adversary. The paternity of the concept of asymmetric warfare goes back to Sun Tzu in his Art of War, in the 5th century B.C. This idea is taken up by General Wesley Clark in an article dealing with the second Intifada in 2000 [3], before being integrated into all the doctrines of Western armies. References to intensity are therefore sometimes abusively associated with the parity, or disparity, of the belligerents' capabilities, as well as with the importance of the political-military stakes of a conflict. High intensity" is thus sometimes restrictively associated with the conjunction of major stakes and a symmetrical adversary. Conversely, "low intensity" is often confined to the combination of limited stakes and an asymmetrical, or asymmetric, enemy. However, the Korean War, the Falklands conflict or the Gulf War in 1990-91 escape this single reading grid. High intensity" cannot therefore be characterized simply by the level of parity of the adversaries.

Russia's recent intervention in the Ukraine enshrined the concept of hybrid warfare[4 ], which appeared in the mid-2000s to describe the strategy employed by Hezbollah during the 2006 Lebanon war. Although there is to date no agreed definition of the terms "hybrid warfare" either within NATO or in the French doc-trine, this type of engagement is generally understood as a mixed conflict.It involves the use of conventional and unconventional modes of action, regular and irregular adversaries, and clashes extending to immaterial fields (cyber, influence , disinformation and subversion operations ). Apart from their simple analytical and descriptive value, this concept and its corollaries (hybrid adversary and threat, non-linear warfare, etc.) do not fundamentally revolutionize the understanding of conflictuality.

Most, if not all, wars in human history are characterized by interconnected threats and the use of asymmetries exploiting an adversary's weaknesses in all dimensions of confrontation. Perhaps the most explicit illustration of what a hybrid conflict can be is that of the Hundred Years' War, the outcome of which was marked as much by highly conventional confrontations such as Crete as it was by the war between the two countries.cy (1346), Azincourt (1415) or Castillon (1453), as well as by the "small war" led by Bertrand du Guesclin from 1354, or with the ideological instrumentalisation around the Pucelle d'Orléans from 1429. Conflictuality, especially when it is marked by an imbalance in the balance of power, thus always leads to complex situations involving de facto a form of hybridity. "Today we are witnessing a return of the power states. It is not reflected in the return of the "great patriotic war", characterised by the scale of its means and manpower. It is accompanied by an extension of the areas of conflictuality, beyond the so-called "classic" or "conventional" circles" [5]. This concept of hybridity, even if it remains useful to take into account, is therefore not a sufficient criterion to qualify the intensity of a conflict.

The notion of intensity actually emerged with the emergence of the concept of Low-Intensity conflicts, allowing Western strategists to describe, from the 1960s onwards, certain types of specific operations, such as counter-insurgency. However, this notion remains particularly ambiguous, even highly debatable, depending on the level considered. Thus, in so-called "low-intensity" conflicts, engagements at small tactical levels can be extremely intensive in terms of violence, losses, the variety of means used, consumption, damage, etc. Similarly, "high-intensity" and "low-intensity" sequences may coexist during the same campaign. It may therefore be useful to distinguish between tactical high intensity ( there is violent combat , but the battle is limited to a more or less artificial addition of simultaneous or sequential engagements); "operative" high intensity (the battle is not a tactical one); and "operational" high intensity (the battle is not a tactical one). (the campaign comprises battles, i.e. violent engagements involving all the forces and the full range of means of warfare, in a theatre within a given space-time framework); and strategic high intensity (from major conflict to all-out war ).

Faced with the multiplicity of contexts and levels of intensity likely to be encountered on the battlefield, the need to develop and conceptualize "multi-intensity versatility" became apparent in the late 1990s . The notion of " three block war " was first enunciated by USMC General Charles Krulak[6] in 1997 to describe the broad spectrum of conditions under which Western forces could be brought to act during futile engagements. Fundamentally, it is a question of land forces being able to conduct simultaneous large-scale coercive operations, peacekeeping and humanitarian assistance in contiguous field compartments. The main conclusion of this concept is that command training at the lowest levels needs to be particularly advanced to achieve this capability. This particular point leads Krulak to refer to what he calls "strategic corporals", low-level heads of tactical entities capable of taking major decisions autonomously. French land forces doctrine for its part has taken the decision to insist on the notion of reversibility . However, this should be understood more as "the ability to change rapidly the mode of action taken in response to the general attitude of the adversary, in particular in order to keep an operation at the lowest possible level of intensity" .

1] National Security and Defence Strategic Review, 2017.

https://www.defense.gouv.fr/content/download/514684/8664656/file/2017-RS-def1018.pdf.

2] Von Clausewitz, Carl, De la guerre, 1832, reprinted. Tempus, 2014.

3] Tennenbaum, Elie, Le piège de la guerre hybride, Focus stratégique n° 63, Institut français des relations internatio-nales, October 2015.

https://www.ifri.org/sites/default/files/atoms/files/fs63tenenbaum_1.pdf.

4] Clark, Wesley, How to Fight an Asymmetric War, Time, 23 October 2000.

http://www.time.com/time/magazine/article/0,9171,998272,00.html.

5] Krulak, Charles, " The Strategic Corporal: Leadership in the Three Block War", Marines Magazine, January 1999.

http://www.au.af.mil/au/awc/awcgate/usmc/strategic_corporal.htm

6] Army, General Tactics (FT02), 2nd edition, Economica, 2014.