The Law and Character of War in 2035

by , | Mar 25, 2022

Changing Character of War

In fall of 2020, the Lieber Institute for Law and Warfare at West Point joined a U.S. Army Futures Command (AFC) multi-year study on the changing character of warfare. The study has convened three times annually since. Its purpose is to predict and identify adaptations required for the United States to win a future armed conflict against a peer adversary.

From its operationally privileged vantage point, the study has suggested that some existing or emerging law-of-war notions may exact high operational costs or would hinder resort to militarily necessary weapons, tactics, or operations during future warfare. Later phases of the study will no doubt bring into relief legal evolutions needed to ensure the laws of war remain compatible with war. Many such evolutions may also become apparent from the current Russia-Ukraine conflict. The study and the conflict present an opportunity to consider whether States will be prepared and willing to adjust seemingly settled and even tested international law rules. More generally, the study presents an opportunity to consider whether the broad twentieth-century balance between humanity, necessity, and sovereignty—including its trend toward greater and finer restraints on belligerent conduct—is no longer sustainable or desirable.

The Character of War

The Futures Command study focuses on the year 2035. It assumes hostile relations between the United States and a State adversary of roughly comparable capabilities and resources. An impressive group of experts from a variety of professional disciplines has provided detailed military, political, and technical assumptions. Scientists, technologists, and engineers deeply familiar with emerging and anticipated military technology have taken part in all stages of work. Technologies such as artificial intelligence (AI) and machine learning, robotics, computer science, quantum computing, and synthetic biology have featured heavily throughout.

Equally important to the study is a diverse representation of the military operational community. Experts in each of the Army’s warfighting functions, as well as members of specialized communities such as cyber and special operations have participated. The study has already provoked rich technological and military operational discussions based on the most informed current estimates of the anticipated conditions for future armed conflict.

Implications for the International Law

In legal terms, the study calls for the familiar task of determining whether operations and technology are lawful under the existing international legal regime. In the language of military staff work, the study considers whether proposed operations are “legally sufficient.” But the study also presents a more challenging and compelling opportunity to consider whether the law is “operationally sufficient.” That is, the study’s long-term focus offers a rare opportunity to identify legal adaptations or evolutions that might be necessary or desirable for 2035 warfare.

In most cases, we found that time-tested rules and principles of the laws of war would serve operational interests well, even in 2035. Yet in some cases, discussion of projected conditions of armed conflict have suggested new or increased tension between the anticipated demands of military operations and existing international legal doctrine. In most of these latter cases, further refinement of projected operational concepts and greater details of operational needs are required to identify precise legal adjustments. Nonetheless, we have identified several areas in which anticipated developments raised questions about the viability of current legal doctrine.

The Competition-Conflict Continuum

The study has focused on the tactical and operational levels of war.  Thus, legal considerations have largely related to the conduct of hostilities rather than to the political and strategic questions that surround decisions to resort to force in the first place. However, the study’s predictions about the likely scope, intensity, and character of future international relations have raised questions about applicability of war rules and especially the well-known and putatively refined legal threshold of armed conflict. While many of the study’s proposed operations could clearly be characterized as taking place either within or outside of armed conflict, others have involved competitive, disruptive, unfriendly, and even hostile conduct that did not clearly amount to war or take place during armed conflict. These operations have raised questions about the future relevance of strictly binary legal notions of war and peace.

Of course, much of existing international law still rests in significant part on a formal distinction between times of peace and of war. And while many States’ legal views are relatively clear with respect to restraints on the conduct of war, views on various peacetime limits on international relations remain relatively cloudy. They are perhaps still cloudier in the uncertain territory between peace and war. Several sessions of the study have envisioned persistent competition between adversaries below the thresholds of violence and State attribution envisioned in conventional conflict. The study often adopted the term “left-of-bang” operations in this context.

For example, pre-conflict deployment of special operations forces has appeared prominently in all phases of the study as it reportedly did in the Ukraine conflict. Given the potentially rapid acceleration of events toward war and the likely high tempo of warfare (discussed below), the study has predicted that States will face enormous pressure to pre-position forces and materiel in adversary territory. The study identifies significant military advantage to operations carried out in anticipation of hostilities as “battlefield preparation.” Such left-of-bang operations might include sabotage, intelligence gathering, propaganda, and psychological operations to undermine the adversary’s ability to transition quickly to armed hostilities as well as to weaken civilian support in adversary territory.

During a particularly provocative session, it was suggested that a State’s covertly emplaced special operations forces might distribute or scatter mobile phones in an area of operations. When used by the population, these phones would serve as information-gathering sensors, alternative or back-up communication networks, and even channels for the remote delivery of non-kinetic effects. Indeed, the conflict in Ukraine appears to have confirmed that mobile phones may play an important role in intelligence collection. The perceived necessity and military advantage of such operations could strain prevailing and emerging legal notions of civilian insulation from military operations.

In a similar vein, the study identified an important role for proxy forces. Military planners expect proxies to be a persistent feature of relations between major powers. The study projected proxy groups and forces would play a critical role in pre-conflict battlefield preparation of the kind referred to above. Covertly emplaced special operations forces may be used to identify, contact, and develop dissidents and resistance groups in enemy territory. Study participants often referred to proxies as “force multipliers,” exponentially increasing the volume and effectiveness of sub-armed conflict threshold efforts to undermine an adversary’s ability to transition quickly to hostilities.

We suspect that as clearer pictures of operations below armed conflict thresholds and above fully peaceful or friendly conditions emerge, potential clarifications and even adjustments to peacetime restraints including limits on violations of sovereignty, on intervention, and on resort to countermeasures may take shape as well.

Additionally, there were indications that existing law may not assign State responsibility effectively.  Specifically, lax theories of responsibility may not make effective responses and countermeasures against proxy operations sufficiently available to victim States. For example, the shortfalls of the customary rules governing the responsibility of States for the internationally wrongful acts of non-state actors are well documented. These shortcomings may lead States to advocate and develop amongst themselves more effective international rules and norms concerning responses to proxy and counter-proxy operations.

Finally, the operations envisioned short of armed conflict highlighted an important question concerning the source of legal authority to undertake belligerent acts. The study considered the possibility of conducting lethal or destructive operations along a continuum of competition between States or against non-State actors. In this respect, we noted that certain legal circles envision the law of armed conflict as serving an authorizing function in some contexts. Setting aside the question whether the law of armed conflict is a source of legal authority to States or combatants (see section 10.1), it is at least clear that a state of armed conflict is not a legal prerequisite to engage in military operations. Accordingly, we suspect States may soon wish to express views on the source of authority to initiate such operations as well as the complex interplay between notions of State sovereignty and international legal regimes such as the jus ad bellum, jus in bello, and human rights law.

Command and Control

The study indicated significant changes to the exercise of command and control. Doctrinally, command and control refers to the “exercise of authority and direction by a properly designated commander over assigned and attached forces in the accomplishment of the mission.” It is now clear that future combat operations will occur at a speed that often exceeds human cognitive capabilities. The study envisioned that States will deploy algorithmic-based tools that aid or perhaps even replace, to some degree, human decision-making. An example involved the use of AI in an urban area of operation. In mere seconds or even fractions thereof, AI could consider and evaluate dozens of potential routes through or around urban defensive positions, and recommend or decide upon the route most likely to further operational objectives.

Less appreciated perhaps is the high tempo at which future operations will occur. Distinct from speed, tempo is the “relative speed and rhythm of military operations over time with respect to the enemy” (emphasis added). States’ operations centers, communications networks, and even weapons will be linked to allow combat operations to occur at a stunning tempo. Military analysts have attributed lack of operational tempo as a major failing of the Russian invasion of Ukraine. In future wars, the greatly accelerated pace of operations will require delegated decision-making authority both with respect to subordinates and non-human decision-making capabilities. During the study, experts have referred to managing “levers of authority.” The study expected that military decision-makers will manage a complex set of command levers, the manipulation of which will adjust the delegation of authority across multiple levels of command. The exercise of authority will be a constant and demanding process, that reacts to or even dictates a breakneck speed and tempo of warfare.

The legal implications of the speed and tempo of future warfare are significant. Here, we will highlight only two. First, it seems a foregone conclusion that States will delegate much operational control and decision-making to non-human tools and capabilities. Already, a robust debate addresses preservation of minimum levels of human control or human judgment in the conduct of hostilities. We will not rehash that debate here, but we note the risk of such discussions failing to account for the anticipated and very compelling conditions of war—wars between States in which victory or defeat can be determined in mere fractions of an hour. One of the most jarring aspects of the study has been projections about how willing some States may be to “flip the autonomy switch,” thereby delegating a remarkably broad segment of targeting operations to autonomous systems. At least in high-tempo phases of warfare, legal notions requiring human control over all decisions about individual targets seemed untenable at some points in the study.

Second, the study reinforced the impression that evaluations of law-of-war targeting rules must account for new operational impacts and incentives. For example, the study devoted significant thought to how sustainment, resupply, and other logistical operations can keep pace with the speed and tempo of future armed conflict. Logistical operations have profound impacts on targeting operations, which after all rely heavily on steady and reliable supplies of fuel, ammunition, weaponry, vehicles, and other equipment. Logistical challenges have plagued Russian formations’ advances into Ukraine and are an object lesson in the cost of supply failings. The days of States bringing the “iron mountain”—an all-encompassing and comprehensive supply of warfighting resources—to the theater of operations appear to be over.

The study has anticipated aggressive and highly destructive or disruptive adversary operations directed against production and resupply points. The feasible precautions and protective measures made possible by previously robust and redundant logistical structures may be greatly reduced in such a logistically challenged environment. While the law-of-war feasibility standard already accounts for varied context, adjustments to precautions and protections now largely taken for granted as feasible in all circumstances may be forthcoming.

Deception and Distinction

Last for purposes of this post, the study featured constant tension between battlefield data-gathering capabilities and the need for security in military operations. With respect to the former, study participants predicted omnipresent data-gathering devices on both sides of the conflict. Not only will belligerents deploy data-gathering sensors across every anticipated operational domain, sensors will be small and inexpensive enough to be deployed seemingly everywhere at once. States will inevitably exploit the ability to watch every stage of adversary operations from deployment to combat and after.

Information gathering capacity will place enormous pressure on States to protect and secure their military operations against adversary discovery and attack. In this regard, deception has featured as an imperative character of war throughout the study. Participants have consistently offered the view that war would get “sneakier.” At times it seemed that any military objective or combatant that appeared to be what it actually was would not survive. Omnipresent sensors will tempt belligerents to engage in forms of deception that suggest or mimic protected statuses such as civilian, civilian object, and medical personnel and equipment.

The legal line between lawful deception and unlawful treachery or perfidy is already a fine one. States will grapple with serious questions about how security and concealment operations will place protected persons and objects at risk. More relevant here is the fact that States must give careful thought to whether and how legal restrictions on deception in warfare must be adjusted or can be accommodated in light of these anticipated operational developments.


The Lieber Institute’s participation in the AFC study has proved a promising, if at times daunting, starting point for future exploration, development, and cooperation with the Army’s operational community. The study is an extraordinarily rewarding opportunity to live out our mantra, that law of war analysis requires acute awareness of and sensitivity to military and operational realities. We find ourselves better positioned to inform and advocate for laws of war that are simultaneously as operationally relevant and as humane as they can be.

As we continue the AFC study, we hope to offer the law-of-war community more finely tuned understandings of future warfare and of the demands it will place on law. In turn, we hope to identify and hone the legal adjustments that may be required to maintain and develop an “operationally sufficient” law of war. While we are confident that most of the time-tested principles and precepts of the law of war will prove adequate to meaningfully vindicate military necessity, sovereignty, and humanity, we remain willing to question existing and emerging regulations. From an operational perspective, we owe our fellow study participants clear-eyed and honest assessments of the law as it is and as it might be, whether in favor of necessity, humanity, or sovereignty. From an academic perspective, we are excited, as always, by the opportunity to model an operationally informed outlook on the regulation of the conduct of hostilities.


Sean Watts is a Professor in the Department of Law at the United States Military Academy, Co-Director of the the Lieber Institute for Law and Land Warfare at West Point, and Co-Editor-in-Chief of Articles of War.

Robert Lawless is an Assistant Professor in the Department of Law and Managing Director of the Lieber Institute for Law & Land Warfare at the United States Military Academy, West Point.



Photo credit: U.S. Army Sgt. Thomas Calvert