A much more subjective notion than it seems, high intensity is above all a question of reference. Thus, in military literature as in soldier imagery, this qualifier seems to apply at all levels, from the general strategic context to the local tactical situation.

In its primary historical sense, high intensity refers to inter-state conflicts [9]. 9] It would therefore be first and foremost a general context in which all the forces available to States would be used to achieve political-strategic objectives. The propensity to escalate or spread is also important: some consider high intensity to exist "when [local conflicts] have the potential to lead to regional destabilization and the intervention of major military powers" [10 ]. 10] The high-intensity context would therefore be characterized by a major political risk for a country, a total confrontation justifying the involvement of all state resources: economic, diplomatic and military [11]. However, the subjectivity of the definition remains, even in such a framework. The asymmetry of the stakes between the powers means that war can be existential for one of the parties, while being of relative interest to the other. The Balkan conflicts of the 1990s (Bosnia-Herzegovina, Kosovo) could legitimately fall under the HI for Serbia [12] whereas they were only external operations for France.

Beyond the general context, high intensity is also evoked to describe a typology of military operation. According to this reading, the nature of the adversary (which may or may not be a State) and its means of opposing our will, define the intensity of the operation: by mirror effect, this estimation implies the forces necessary to extract victory and the price (economic, material, human) to consent [13].

The enemy's capabilities, such as its A2/AD [14] or electronic warfare component, for example, would be a determining criterion. In the same way, without any real scale, an HI operation would be characterized by its large volumes of troops and equipment deployed. The Ukrainian conflict of 2014 is thus considered to be of high intensity since its fighting "pitted 30,000 Ukrainians against each other, deploying about 2,000 armoured infantry vehicles and 600 tanks, facing 2,000 separatist fighters" [15] . 15] If the qualification of HI is based on means, it is also a question of strategic choice: a belligerent can decide on its own level of investment, which will depend on its way of fighting [16].

16] Finally, HI is also available at the tactical level. Since modern warfare is characterized by the volatility of violence, extremely intense fighting can take place in the context of a stabilization operation. Some heads of corps returning from Barkhane do not hesitate to describe their stay as a "high intensity mandate " [17] . 17] More objectively, in August 2008, during the battle of Uzbin, although they were carrying out a 'security assistance' mission in Afghanistan [18], French soldiers nevertheless faced conditions that had the doctrinal characteristics of the HI : involvement of all operational functions (aviation, artillery, helicopters, UAVs), inter-allied coordination, mass casualties, etc [19]. 19] These extremely violent tactical situations during low-intensity operations sometimes lead to the assertion that "it is more appropriate to speak of high-intensity phases [rather than conflicts]", which can be "lasting from a few hours to a few days" [20] .

20] Thus, in the military corpus, high intensity is alternately linked to a general strategic context, an operation, capabilities, or even a specific tactical situation, without necessarily being linked from one field of the spectrum to another. An objectively low-intensity conflict can be the theatre of combat perceived as HI and vice versa. The subjectivity and imprecision of the notion remains and justifies the need for a definition that would be both precise and exhaustive.

From the search for a definition to the affirmation of an ambition

Giving a definition to high intensity would allow an army to show its level of ambition. Saying that it wants to have the capabilities to deal with high intensity is very relevant, but what HI are we talking about? Is it a question of facing a "near - peer Competitor" [21] in an existential war or of being able to resist localized and time-limited tactical situations? In either case, the capabilities to be developed could be very different and would not necessarily depend solely on military will.

If, as is generally understood, HI is defined as a total confrontation between two states or two relatively comparable alliances of states, the capabilities to be held, developed or planned for go far beyond the military domain. Political involvement is paramount and at all levels, especially diplomatic (solidity of treaties) and economic (finance law). In this area in particular, being able to engage in a high-intensity conflict means having a DTIB [22] capable of rising to meet all the qualitative and quantitative needs of a war. On the military level, preparing for such an eventuality implies stockpiling equipment and resources, mobilization plans (initially reserves, possibly conscripts) and regular mobilization training [23]. Preparing for war is a political act that is not insignificant, which requires interministerial action and the understanding - and therefore preparation - of public opinion, the only guarantor of the Nation's resilience. Regardless of the current state of the threat in Europe, the question arises: is such a level of ambition still audible in the West?

If "facing up to high intensity" consists above all of engaging in difficult external operations, in the face of a state or irregular adversary requiring a high level of commitment, then this ambition essentially concerns the military. It is a question of acquiring, developing or maintaining so-called "top of the spectrum" capabilities to oppose their own. In the air domain, this may concern stealth to free oneself from enemy A2/AD measures or the use of HALE or MALE UAVs [24]. Being able to deliver fire in great depth (in particular long-range tactical missiles) is also often mentioned, whether they come from air, land or naval vectors. Other operational capabilities could prove indispensable such as ground-to-air defence (especially if air superiority is contested), electronic warfare, cyber offensive, CBRN [25], etc. The recurring problem of mass scarcity [26] - and its corollary, the reduction of lethality - may also invite to consider the use of combat robots [27]. In short, if there is a common point to these capabilities, it is their high technological level and thus their cost. Perhaps less politically sensitive than the preparation for all-out war, this level of ambition requires, however, substantial funding, ideally maintained over several legislatures. Paradoxically, in the case of external operations, the effort to be made is less understandable to the people, particularly in times of budgetary tension.

Finally, if high intensity is only considered as a one-off situation that can be addressed in the framework of regular operations, the preservation of some pre-existing key capacities could suffice. The adjustments would be mainly technical and operational: improving contact intelligence, coordination in the third dimension (in particular to ensure air-to-ground and ground-to-ground fire support), maintenance of the on-board armoured combat capability, improving personnel protection, etc. The aim would be to improve the quality of the air-to-ground and ground-to-ground fire support. Efforts could even focus on optimising the use of existing assets, for greater responsiveness and effectiveness, rather than on developing new capabilities. Such a delimitation of HI at the tactical level would show limited ambition. Requiring only minimal political involvement, an army accepting this definition could boast, with limited investment and without perjury, of being able to deal with high-intensity situations.

Conclusion: as always, the weight of words.

As in many other areas, the meaning of words and their definition can have far-reaching implications. The notion of "high intensity", which seems so telling, is in fact much more floating than it seems, in its legal and military meanings. Even within the armed forces, HI refers to very different perceptions ranging from a geostrategic context to a localized tactical situation, and the official terminology remains very ambiguous. Finding a suitable definition for the concept requires great caution. Explaining what "high intensity" armies have to deal with means displaying a level of ambition that stems from an asserted political vision, a necessary precondition for ensuring that they have the corresponding economic and societal support.

Two pitfalls can then be identified for armies. The first would be to see in high intensity only the "all-out war" aspect, at the risk of proposing to politicians a model of forces and a message that would be unrealistic, even unacceptable. The other, more pernicious, would be to settle for a tactical definition. Much more politically neutral, this vision would confine armies to a minimum development of high-end capabilities , while maintaining the illusion of being able to cope with the worst situations.

This is the paradox: since the stakes may well exceed the prerogatives given to the military, should the exact wording of this definition not be left to the highest strategic and political authorities? In France in particular, where engagement at the top of the spectrum is envisaged above all in a multinational framework, the definition of this concept could even be undertaken in an "interallied" manner. This is just one way of making our country's level of ambition more transparent to our partners.

9] "high intensity [refers to] conventional war between two states (WWI, WWII, Arab-Israeli Wars, Gulf War I, etc.); low intensity [to] all operations other than conventional war". Dr. Daniel Marston, Force Structure for High- and Low-Intensity Warfare: The Anglo-American Experience and Lessons for the Future, Royal Military Academy Sandhurst, 2004, available at http://www.offnews.info/downloads/2020force_structure.pdf .

10] https://major-prepa.com/geopolitique/guerre/ accessed 6 May 2019.

11] "The full range of armaments, including weapons of mass destruction, can be used not only against military objectives, but also against economic and social infrastructure," definition of "high-intensity conflict," Canadian Terminology and Linguistic Database (Termium+), available at http://www.btb.termiumplus.gc.ca/tpv2alpha/alpha-eng.html?lang=eng&i=1&index=alt&codom2nd_wet=1 accessed May 7, 2019.

12] This is how these two conflicts are sometimes described. Bruno Tertrais, "La Guerre", Que sais-je collection, PUF, 2nd edition, June 2014.

13] On this subject, see Serge Caplain, "Penser son ennemi : modélisation de l'adversaire dans les forces armées", Focus Stratégique n°82, Ifri, July 2018 available at https://www.ifri.org/fr/publications/etudes-de-lifri/focus-strategique/penser-ennemi-modelisations-de-ladversaire-forces .

14] Anti-Access / Area Denial: denial of access and zone interdiction.

15] Hearing of General Pascal Facon, Minutes of the National Defence and Armed Forces Commission, 25 September 2018, available at http://www.assemblee-nationale.fr/15/pdf/cr-cdef/17-18/c1718074.pdf.

16] "Having chosen or identified the intensity, the planners can deduce the operational actions most suited to defeating the enemy" Eado Hecht, Limited or Total: beyond discrete sets of intensity, January 2017, available at https://thestrategybridge.org/the-bridge/2017/1/10/limited-or-total-beyond-discrete-sets-of-intensity .

17] Colonel François-Régis Dabas, "L'opération Septentrion, une action globale interarmées", Fantassins magazine no. 41, Autumn-Winter 2018, p. 98.

18] NATO's ISAF (International Security Assistance Force) operation.

19] On this subject, see the study by Colonel Michel Goya on https://lavoiedelepee.blogspot.com/2019/05/retour-sur-lembuscade-duzbin.html.

20] https://conflictualitemediation.wordpress.com/2013/05/12/le-combat-de-haute-intensite-actualite-de-demain-retour-sur-la-table-ronde-du-club-sup-mer-du-18-avril-2013/.

21] American expression designating a quasi-symmetrical conflict with another power with a global vocation. https://www. usmcu.edu/Portals/218/CAOCL/files/ConsideringRussia%20(004).pdf?ver=2019-04-17-132431-910.

22] Defence Technological and Industrial Base.

23] On this subject, see Guillaume Garnier "Les chausse-trapes de la remontée en puissance, défis et écueils du redressement militaire", Focus stratégique n° 52, May 2014. Available on https://www.ifri.org/en/publications/etudes-de-lifri/focus-strategique/chausse-trapes-de-remontee-puissance-defis-ecueils.

24] High Altitude Long Endurance / Medium Altitude Long En-durance.

25] Nuclear, Radiological, Bacteriological and Chemical.

26] Future Land Action: Tomorrow is won today, Army Staff, Ministry of Defence, 2016, p.37.

27] The level of autonomy of these devices is currently the subject of international debate.