In the past year, a growing chorus of voices has warned that the international “rule-based” order—along with the prohibition on the use of force—is unraveling, with the United States poised to withdraw from the very system it once built.
This post does not seek to endorse or refute this contention. Instead, it aims to unpack the conceptual load of such claims. It briefly looks at the current state of the law on the use of force and its relation to the international legal system. Through the lens of history, it highlights the factors that might make or break this framework. The goal is not to lament the possible collapse of the system, nor to insist on its resilience, but to understand the fault lines that may shape its future.
The Ban on Force
Although widely recognized as a jus cogens norm, the prohibition on the use of force has been breached numerous times over the past eighty years since the UN Charter and its Article 2(4) was adopted. This is in part due to the controversies surrounding the content and modalities of the exercise of self-defence against non-State actors and weapons of mass destruction. Another reason is the inaction of the Security Council and the ensuing legal lacuna for tackling security threats outside self-defence parameters. Nor can one overlook that some States, especially major powers, have used force in violation of the prohibition to advance their own strategic interests.
Does this mean then that the prohibition on the use of force has become irrelevant? Not really. Despite these violations of the law on the use of force, States have consistently sought to justify their actions within the parameters or in the spirit of this law, albeit by bending interpretations, employing ambiguous language, or misrepresenting facts. In particular, States have consistently camouflaged their unlawful or questionable uses of force as self-defence, protection of nationals, consent, non-proliferation, or humanitarian concerns, linking these arguments to the parameters of the Charter. Simply put, the law on the use of force has remained relevant, if only because States continue to abide by it or strive to maintain the appearance of doing so.
The reason for this behavior relates to the consequences a State may face in its international relations if seen as breaching the ban on force. The forms of responsibility for violations of the jus ad bellum are varied. They include Security Council Chapter VII measures, judicial proceedings, unilateral sanctions (severing diplomatic relations, expelling nationals, ceasing trade and investment relations, withholding or reducing economic assistance), or sanctions imposed by regional organizations. They are far from flawless. They may be slow to materialize, politically biased, or ineffective, but their presence matters, because, crucially, they exist within an international legal system that, for all its imperfections, still enforces these consequences in some form. Therefore, if the international legal system erodes, the enforcement of these consequences diminishes and the commitment of States to comply with the prohibition, or at least maintain the appearance of doing so, wanes.
The System
The question then arises: are we really at a point where the Charter-based and UN-driven international legal system is eroding or unraveling? As powerful as the United States and its role within the international legal system may be, it would be too simple to equate its potential withdrawal with the demise of the system itself. What circumstances would then precipitate such an outcome? A brief look at the historical examples of pre-Charter international frameworks, such as the Concert of Europe and League of Nations, may be revealing.
Like the United Nations, both the Concert of Europe and the League of Nations were created in the wake of devastating conflict (the Napoleonic Wars and First World War, respectively) to maintain peace. The main tenet of the Concert of Europe was resolving disputes through dialogue, a principle that indeed helped maintain relative peace between European powers, with only five wars during the nineteenth century. What ultimately brought down the Concert was conflict among its members amidst a combination of longstanding and emerging tensions. Notably, the rise of mid- and late-century Polish, Italian, and German nationalist movements, the 1848 revolutions, the Crimean War (1853-1856), the respective unifications of Italy (1870) and Germany (1871), and the pressure late-century nationalistic movements exerted on Austria-Hungary and the Ottoman Empire all pushed the Concert of Europe and its members towards a critical juncture. The formation of rival alliances, the Triple Alliance (Austria-Hungary, Germany and Italy) and the Triple Entente (France, Russia and the United Kingdom), divided Concert members into opposing camps and paved the way to the First World War.
Similarly, the League of Nations was established to prevent war through peaceful resolution mechanisms and showed some success in its early years, despite the United States never becoming a member. However, the League eventually collapsed because of the opposing interests of its members amidst longstanding and emerging tensions. In particular, decision-making in the League Council was dominated by France, Italy, Japan, and the United Kingdom. Germany joined in 1926, but left the organization in 1933, citing the League’s failure to address German grievances on the perceived injustice of the Treaty of Versailles. The Soviet Union joined in 1934 but was expelled by the Council in 1939 for invading Finland. In addition, the 1929-1933 financial crisis, the rise of fascism in Italy and Germany, the League’s failure to respond effectively to the Manchurian, Bolivian, and Ethiopian conflicts, and the withdrawal of Japan and Italy pushed the League towards a critical juncture. The League formally dissolved in 1946, but in reality, it did not survive the Second World War.
What’s Really Dying?
These historical examples contain some similarities and cautionary tales for current challenges, but they also highlight significant differences. First, both the Concert and the League unraveled as a result of a combination of longstanding tensions among members and emerging economic and political developments that pitted the same members against each other, leading them towards a critical juncture. The collapse of these frameworks coincided with the outbreak of the First and Second World Wars, respectively. Both historical examples thus highlight the inherent weakness of systems that depend heavily on the alignment of interests between major powers.
Today, the Charter-based and UN-driven international legal system faces its own critical juncture: the highest number of armed conflicts since 1945; a Security Council deadlocked over major ongoing conflicts; a severe financial crisis across UN entities; U.S. political and/or financial disengagement from UN agencies and other international entities; growing geopolitical tensions and a reemergence of authoritarianism, nationalism, and unilateralism. If one only takes these parallels into consideration, a new world conflict cannot be ruled out. Such an outcome would almost certainly push the international legal system to a rupture and would inevitably render redundant any enforcement of the ban on force.
Such a dramatic change in the international landscape may prove to be the “political shock” facilitating fundamental changes, much like the end of the Napoleonic Wars, the First World War and the Second World War generated new frameworks in the shape of the Concert of Europe, League of Nations, and United Nations, respectively. A less dramatic scenario would see a worldwide conflict avoided and the current international legal system surviving in an ever-diminishing form, with States using force for their own strategic interests, without striving to comply with the law or at least appear to be doing so.
An Optimist’s Perspective on Death
Fortunately, however, these are not the only available scenarios. There are significant differences between, on one hand, the rise and fall of the Concert and the League, and, on the other hand, the possible fate of the Charter-based and UN-driven international legal system. The functioning of the Concert and the League relied heavily on diplomacy, informal or incipient institutional and procedural structures, and limited membership, with decision-making often reflecting the strategic interests of a select few rather than any form of collective good.
Admittedly, decision-making in the UN Security Council is reminiscent of its predecessors: a forum for diplomacy and crisis management rather than a centralized authority prioritizing the collective good over national interests. However, despite growing deadlock over major ongoing conflicts, the Security Council is still active, and significantly more so than it had been through the Cold War. This is due to the permanent members’ common aim of retaining the Council as an institution in which they hold advantages in decision-making. In any event, the mechanisms of the Security Council are today increasingly complemented by a complex regulatory and institutional structure, an “intricate web of legal norms and institutions,” underpinned by a robust tradition of “highly legalized” and “institutionalized” internationalism. Moreover, today, virtually every State is a member of the UN.
These features may hold the solution for the endurance of the contemporary international legal system and within it, the enforcement of the ban on force. As observed by others, it is undeniable that the United States helped build this system. Whether the United States will truly disengage from it remains, for the time being, a matter of speculation. And maybe this is not the right question to ask at this point. The historical examples of the Concert and the League as well as the difficult functioning of the Security Council may suggest that there is merit in imagining a world where the privilege and burden of decision-making does not rest with a select few, where other actors and “sources of power,” guided by the foundational principles of the Charter, fill or complement an emerging power vacuum.
When it comes to the law on the use of force, such alternative sources of power have been increasingly apparent. In particular, the General Assembly has significantly expanded its role in the maintenance of international peace and security amid Security Council deadlock, including with initiatives on Ukraine and Palestine. The International Court of Justice has recently seen an increase in its caseload, including proceedings addressing major ongoing conflicts. The International Criminal Court may still play a significant role in holding heads of States and high-ranking officials responsible for crimes stemming from the unlawful use of force, if States actively enforce its decisions. The Special Tribunal for the Crime of Aggression against Ukraine, backed by the Council of Europe, reflects similar accountability efforts. Regionally, the African Union and European Union manage an increasing number of peace operations, reflecting a growing regional ownership over the maintenance of peace and security. European NATO members have recently agreed to boost their defense spending.
These efforts may not be enough in themselves to counter all of the aforementioned challenges faced today by the Charter-based, UN-driven international legal system. But their combined and coordinated effect may offer a good starting point for enforcing, in one way or another, the prohibition on the use of force and, in doing so, signaling the continued functioning of the international legal system. For now, the rules governing these entities remain aligned with the principles and purposes of the Charter. They also stem from the belief that membership and active participation in international frameworks builds a safer and more stable world. If these and like-minded sources of power assert dominance in the coming years, there is hope that their combined efforts can support or substitute Security Council action in maintaining some form of collective security, ensure accountability for violations of the law on the use of force and, more broadly, reinforce the existing international legal system.
To contribute to this goal, it is our task as international law practitioners and scholars to engage in rigorous legal analysis, partake in or advocate for the enforcement of the law on the use of force through courts, cooperate with and advise governments, international and non-governmental organizations, and engage in the public discourse through publications, presentations and media. Simply put, “[e]ach generation doubtless feels called upon to reform the world. Mine knows that it will not reform it, but its task is perhaps even greater. It consists in preventing the world from destroying itself.”
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Dr Kinga Tibori-Szabó is a practitioner of international criminal law and international humanitarian law.
The views expressed are those of the author, and do not necessarily reflect the official position of the United States Military Academy, Department of the Army, or Department of Defense.
Articles of War is a forum for professionals to share opinions and cultivate ideas. Articles of War does not screen articles to fit a particular editorial agenda, nor endorse or advocate material that is published. Authorship does not indicate affiliation with Articles of War, the Lieber Institute, or the United States Military Academy West Point.
Photo credit: Army Staff Sgt. Kenneth Rodriguez