The law of armed conflict in 2040

In the summer of 2020, the Lieber Institute team and I hosted a workshop at West Point titled “LOAC 2040”. We invited a group of scholars and practitioners of the law of armed conflict (LICA) from around the world, and with a range of perspectives, to examine how this body of law and the institutions responsible for creating, interpreting and to apply it may arise in the next two decades—as well as the opportunities that may exist to influence it then.

The outcome of this workshop—The future law of armed conflictwhich I co-edited with LTC Thomas Oakley of the West Point—East Legal Department now available from Oxford University Press. This is the final volume in the Lieber Studies series under the general direction of Professors Michael Schmitt and Sean Watts.

As I write in the introductory chapter of the new volume (a version of which is available here):

War is changing – and fast. New technologies, new geopolitical alignments, new interests and vulnerabilities and other developments are changing how, why and by whom conflicts will be fought. Just as militaries must plan ahead for an environment in which the threats, alliances, capabilities, and even areas in which they fight will be different than today, they must also anticipate international legal constraints that may to differ.

The workshop identified several broad, overlapping categories of change that are particularly relevant to DCA development.

    • New technologies, such as digital systems, artificial intelligence and hypersonic weapons, are changing military capabilities and vulnerabilities.
    • New and changing domains of conflict, particularly cyber and space, and related “hybrid warfare” schemes involving large-scale information operations, are changing where and how conflicts will be fought.
    • The changing roles of non-state actors, particularly non-state (or loosely affiliated) armed groups, civil society organizations, private companies and legal decision-making processes, are also changing.
    • Changing geopolitical realities, such as the rise of China and the proliferation of weapons of mass destruction, are altering strategic calculations and the distribution of power and influence.

The book’s chapters are roughly organized around these overlapping categories (see here for the table of contents). Their topics nicely complement the US Department of Defense’s recent emphasis on preparing for high-intensity combat operations following decades of operations focused on counterterrorism and counterinsurgency operations.

To help frame the discussion, the LOAC 2040 workshop included remarks from U.S. Under Secretary of the Army James E. McPherson, who spoke about some of the challenges that U.S. defense planners face in preparing for these rapid developments, including large areas of uncertainty. A major theme of the workshop discussions, however, was that none of these developments listed above are entirely new; Some aspects of them have been around for decades, though many of them are accelerating. Therefore, the workshop on the future DCA also included a keynote address by Sir Adam Roberts. This lecture was expanded upon in the opening chapter of the book, in which Roberts urges caution, based on past experience, in trying to predict what future warfare will look like. It also draws from this experience a set of principles to guide efforts to revise or adapt the DCA to meet future conditions, and these ideas run through many of the chapters that follow. This volume is not intended to present a single prediction of the future. Rather, it seeks to present possible and alternative futures and raises big questions and issues that are likely to emerge.

Overall, for example, contributors consider new binding global treaties in this area unlikely. Some of the chapters are optimistic that new challenges and gaps can be partially resolved through the interpretation of existing treaties and customary law, or by supplementing existing law with additional non-binding agreements. Other contributors, however, are skeptical of the convergence of interpretations between powerful states. New challenges are unlikely to break the system, but they will likely warp many parts of it.

There are many reasons why these chapters focus on adapting existing law rather than anticipating new treaty law. As mentioned above, many DCA challenges that are often referred to as “new” aren’t really that new. These are extensions of old challenges, such as applying long-standing Targeting Law principles to critical infrastructure that serves both military and civilian purposes. International negotiations are always slow, but technological change is accelerating, and in ways that are hard to predict. Powerful states are reluctant to engage in the face of divergent or uncertain strategic interests. This last point could change drastically in the event of a major disaster, such as a crippling cyberattack or a highly destructive war involving powerful states, prospects that suddenly seem more likely after Russia’s recent invasion of Ukraine.

Overall, this is a book about legal adaptation. The authors bring to their chapters a wide range of professional and normative perspectives. However, they agree that the DCA must continue to adapt in order to maintain its vitality.


Matthew C. Waxman is Liviu Librescu Professor of Law and Director of the National Security Law Program at Columbia School of Law.