General John Philips is from the Signal Corps. Agraduate of the United Sates Army College, he has been deployed to many theatres of operation, including Iraq, Afghanistan and Kuwait. He is currently assigned to the G6 United State Army Europe.

The emerging concept of multi-domain operations is not yet part of US military doctrine. In this area one can still speak of an experimental phase, with the aim of formalising an associated doctrine by 2028. Similarly, it has taken 10 years to establish their doctrines for air and land combat.

In practice, the aim of multi-domain operations is to enable the armed forces, as part of a joint operation, to compete and, if necessary, to confront and defeat a near-peer adversary in support of the United States' security and defence strategy.

This approach is not new to the US military - having already been successfully carried out with the help of the US General Accounting Office (GAO) in the past, the US Army has been able to use it in a joint operation.neral Rochambeau and Admiral de Grasse, to prevent the retirement of Admiral Cornwallis and to contribute to the establishment of the United States Republic. However, the establishment of a doctrine in this matter, beyond the structural prerequisites, requires practice. With this in mind, the United States Army has developed a first multi-domain intervention force and is in the process of establishing a second one in Europe.

These units integrate a conventional artillery brigade with additional capabilities to make it a targeting unit, pooling all the elements involved in the main operations. However, in the absence of a common organic structure, the ability of these multi-domain units to initiate and coordinate air and naval strikes remains limited.

At this stage, the experiments conducted at Fort Lewis under the command of General Robert B. Brown(US Army Pacific Commander), have already demonstrated the effectiveness of a multi-domain approach. However, he felt that a combined command would need to be established at a higher level to allow full use to be made of air and naval, and even space capabilities.

The multi-domain approach will also require the possibilities offered by new technologies to be exploited. With the arrival of 5G, masses of data will be able to be processed, with almost immediate response times, giving the command the capacity to react more quickly and effectively.

Among the principles of warfare of the American army, three seem to be fully applicable to multi-domain operations, referring to the fundamental principles of French doctrine: economy of forces, mass (i.e. concentration of effort) and unity of command (i.e. freedom of action).

Economy of forces appears essential, since precision munitions are expensive and available in small quantities. In this respect, the multi-domain approach could make it possible to eliminate threats effectively by recourse to non-kinetic means (electromagnetic jamming, information gathering by space-based means, information operations, defensive or offensive cyber operations, etc.).

Mass, on the other hand, requires synchronisation of efforts to defeat an adversary with superior force. This principle is inherent in the multi-domain approach. In this framework, non-kinetic means could also allow better identification of targets whose destruction is likely to produce the maximum effect.

The command of multi-domain forces at a high level would run counter to the desire to develop freedom of action and capabilities at the lowest levels. However, at this stage, the challenge would be to take into account the exercise of national authority to engage in cyber operations. this configuration still limits the speed of action needed to produce non-kinetic effects through such operations. At the same time, the challenge would be to be able to better measure the aggregate effects of such operations. It will also be necessary to study how these principles can be applied in the cybernetic and space domains.

In addition, the US military applies a fourth principle: simplicity. This principle is essential in the context of multi-domain operations, given their extreme complexity. We strive to apply this principle down to the lowest level to improve our ability to conduct such operations.

To implement multi-domain operations, we will first need to rely on allies. The challenge will therefore be to develop interoperability, by federating national "secret/releasable" networks to enable instant data sharing in a common operational environment. At the same time, it will be necessary to invest in the field of cyber defence in order to avoid falling victim to multi-domain operations.