Roundtable Blog:
After the Rupture: International Lawyers Reckon with the Disruption of the Rules-Based Order
Editor’s Note
This post is part of the PILPG Lawyering Peace working group series. It presents a curated set of expert reflections drawn from a roundtable discussion held in March 2026. The experts examine one of the most consequential questions in contemporary international affairs: whether the post-1945 rules-based international order is experiencing a temporary disruption or a fundamental, potentially irreversible rupture. The roundtable also contributes to a forward-looking policy conversation: what can international lawyers, policymakers, and civil society do to adapt or respond.
A simple question was discussed at the outset: Are we overreacting? What followed was, rather than a debate, an agreement among experienced international lawyers and policymakers, coalescing into an unambiguous no. The more troubling possibility, several experts suggested, is that the world has not yet grasped the full magnitude of what is already underway.
Drawing on the diverse expertise of our Peace Fellows, this post moves beyond the immediate headlines and examines the structural forces at work, characterizing the moment, tracing its causes, and asks what international lawyers, policymakers, and middle powers can realistically do in response. Published under the Lawyering Justice banner, this post reflects our commitment not only to chronicling the legal and diplomatic dimensions of active conflicts, but also to fostering strategic foresight and connecting lawyering to policy planning. We hope this format will serve as a model for future collaborative work on peace and justice.
Characterizing the Moment
Before addressing causes, consequences, or responses, the working group spent considerable time on a terminological question that turned out to carry real analytical weight: is what is happening a paradigm shift, an evolution from one coherent order to another? or something more sudden and less legible?
Dr. David Crane, Founding Chief Prosecutor of the UN Special Court for Sierra Leone and Founder of the Global Accountability Project
Dr. Crane opened with a rejection of the premise embedded in the question. “We are not overreacting,” he said. “I am not sure what overreacting even means in this day and age.” He reached for the image of a kaleidoscope: a change in which, when one element shifts, everything simultaneously reconfigures. The scale of the disruption, in his reading, places us at or near a threshold that previous generations associated with world war. “We are on the verge of World War III,” he said, “or we can argue it has already begun.” The implication is not panic, rather a call for clear-eyed urgency. Dr. Crane emphasized the need to think about how we keep ahead of the paradigm shift, through patience and scholarship.
Ambassador Jorge Lomonaco, former Ambassador of Mexico to the UN Human Rights Council and to the Organization of American States
Ambassador Lomonaco pushed back on the premise of the opening question. The concern, in his view, is not that the international community is overreacting to current events but that it has not yet fully reckoned with their scale. The situation is considerably worse than most have yet grasped. Later in the session he returned to the terminological debate with a precision that reframed the entire discussion. A paradigm shift, he argued, implies that something new is already taking shape to replace what is being lost.
History offers examples such as the shift from the multipolar European order to the bipolar Cold War, or from the Cold War to the post-1991 moment of American primacy. In each case, the contours of the successor arrangement became visible relatively quickly. What the world is facing today is different. The post-1945 order has not shifted toward something recognizable; it has fractured, and nothing coherent has yet emerged to take its place. In other words, “the paradigm is broken,” he said. That distinction, between a shift and a rupture, carries real consequences for how policymakers and legal practitioners should respond. Planning for a transition assumes a destination. Planning for a rupture requires a different kind of thinking entirely.
Ambassador Keith Harper, former US Ambassador to the UN Human Rights Council
Ambassador Harper refined the terminology directly. “I don’t know if it is a paradigm shift so much as a rupture of the paradigm,” he said. “The question is what replaces it.” For Ambassador Harper, that question is not rhetorical. He pressed the group toward a longer historical view, drawing on two of the twentieth century’s great moments of deliberate institutional construction. The first was the preparatory work that preceded the Paris Peace Conference of 1919, where Woodrow Wilson and a team of lawyers, academics, and diplomats spent months drafting proposals for what a post-war international order should look like before a single negotiation had begun. That preparation produced the blueprint for the League of Nations.
The second was the drafting of the UN Charter in 1945, where Allied powers translated the wreckage of World War II into a new architecture of collective security, international law, and multilateral cooperation. Ambassador Harper’s point was that neither of those moments happened by accident. They were the product of deliberate, advanced thinking about what kind of world the next generation of states wanted to inhabit. His argument was that this moment calls for exactly that kind of effort again: a serious, forward-looking rethinking of how multilateral institutions should be designed, how alliances should be structured, and what shared rules should govern a world that looks nothing like the one those earlier architects faced. His hope is that American politics will ultimately recognize the current trajectory for what it is and that space will reopen to do that work alongside allies.
The American Recalibration: Cause or Symptom?
The Trump administration’s reorientation of American foreign policy is the most visible driver of the current disruption. But several experts pressed a harder question: is the US the cause of the rupture, or the symptom of forces that would have produced it regardless?
Ambassador Julian Braithwaite, former British Ambassador to the WTO, UN, and Other International Organizations in Geneva
Ambassador Braithwaite traced a line through three successive Western military interventions in the Middle East, each one revealing something about the state of the international order at the moment it occurred. The 1991 Gulf War, launched in response to Iraq’s invasion of Kuwait, was authorized by the UN Security Council and assembled one of the broadest multilateral coalitions in the post-war era. It represented the rules-based order functioning close to its intended design: collective authorization, shared burden, declared objectives.
The 2003 invasion of Iraq showed a more complicated picture. The legal basis was disputed, the coalition was narrower, and the objectives became increasingly difficult to define as the conflict deepened. But the US and its partners still operated within a framework of justification, however contested, and still sought to build an international rationale for what they were doing.
The current situation represents something categorically different. For instance, the current US-Israeli invasion of Iran is neither accompanied by a UN Security Council resolution, nor a justification or alliance.
What that sequence reveals, he argued, is not simply a change in American behavior under a particular administration but a structural trend that has been building for decades, and that is the progressive erosion of the multilateral architecture that once gave military action its legitimacy. The rules-based international order was never a purely principled construction. It was built to serve interests and it functioned because powerful nations were willing to act as the enforcer of last resort when the system’s norms were violated. As the costs of that role grew and the domestic political appetite for it diminished, the system began hollowing out from within. Without the state that designed and underwrote it, the architecture does not simply weaken, it atrophies.
Dr. Igor Lukšić, Former Prime Minister and Foreign Minister of Montenegro
To Dr. Lukšić, the absence of UN Security Council authorization for major military action is not a new phenomenon. The historical record reflects a pattern in which the use of force has often proceeded outside the Charter framework, with outcomes shaped heavily by prevailing geopolitical dynamics. The US-led military intervention in Korea in 1950 was formally enabled by a Security Council mandate secured only because of the Soviet Union’s temporary boycott; the 1999 NATO intervention in Yugoslavia unfolded without any Council authorization; and the 2003 US invasion of Iraq proceeded without explicit UNSC authorization, justified instead through contested claims about weapons of mass destruction and existing UNSC resolutions.
By contrast, the response to Iraq’s invasion of Kuwait in 1990 did receive Security Council approval. In many cases, military action undertaken outside the Council’s prior authorization was later followed by Security Council engagement or resolutions addressing the evolving situation. The current situation, where military force is being deployed outside the framework the UN Charter was designed to provide, is not, on that dimension alone, historically unprecedented.
What is different, and what makes the present moment genuinely novel, is the simultaneous layering of multiple crises across different regions and domains, combined with a pace of change that is outrunning the capacity of institutions and governments to respond coherently. The world, in his framing, has moved past the era of clear American primacy that defined the post-Cold War decades, but it has not arrived anywhere new. It occupies an unstable in-between, it is no longer unipolar, not yet genuinely multipolar, and without an agreed framework for managing the competition that fills the space between those two conditions. Dr. Lukšić was candid about the limits of what anyone can predict from this position. The process of finding a new equilibrium will be long and structurally disruptive, he emphasized. “It will be a painful process that will lead to something, what exactly is hard to say, but it will have to be another rules-based order.”
Speed, Enforcement, and the Deliberate Demolition
Ambassador Elizabeth Richard, former US Ambassador to Lebanon & Coordinator for Counterterrorism / Ambassador at-Large
What the international community is witnessing, Ambassador Richard argued, is not improvised disruption but a deliberately designed strategy, and its central instrument is speed. The logic she described is one that anyone familiar with legal and institutional processes will recognize: rules-based systems, whether domestic courts, international tribunals, or multilateral bodies, operate on timelines. Investigations take months. Litigation takes years. Treaty renegotiation takes longer still. When governments move faster than those timelines, they can reshape facts on the ground before any accountability mechanism has had time to engage. Withdrawal from international agreements, defunding of multilateral institutions, reassignment of treaty obligations, restructuring of alliances, each of these actions is considerably easier to execute than it is to reverse, and that asymmetry between dismantling and rebuilding is not incidental.
It is, in Ambassador Richard’s reading, the defining feature of the current moment. “Eventually the law may catch up, but by the time it does, you cannot put the pieces back together again.” That observation raises a question she left deliberately open: if the space vacated by retreating multilateral engagement cannot be reclaimed through legal or institutional challenge in real time, can a coalition of middle powers construct and enforce a values-based alternative before that space is filled by something else entirely?
States like Canada, the UK, Germany, Japan, and Australia individually lack the singular weight of a great power, but collectively they represent significant diplomatic, economic, and normative influence. The question is whether that influence can be organized quickly enough and with sufficient coherence to matter.
Major General Darrell Guthrie, US Army (Ret.)
In agreement with Ambassador Richard, the compression of decision-making timelines is not simply a political phenomenon, Guthrie argued. It is structural, and it has been accelerating for decades. Financial markets now execute transactions in fractions of a second. Information travels across the globe instantaneously. Corporate decisions that once required weeks of deliberation are made in hours. The private sector adapted to that reality long ago, redesigning its institutions, its processes, and its expectations accordingly. However, the international governance system has not. The UN Security Council still deliberates. International courts still move through years of procedure. Treaty bodies still require consensus among dozens of states before anything binding can be agreed. Those processes were designed for a world where the pace of events allowed for reflection, negotiation, and incremental adjustment. That world no longer exists. “An international rules-based order was premised on time,” Guthrie said.
The result is a structural imbalance. Those whose power depends on deliberation and consensus are increasingly disadvantaged, while those willing to treat speed as a strategic instrument gain the upper hand. Institutions that cannot keep pace with the challenges they were built to address do not simply become less effective. They get bypassed altogether, left out of the decisions that actually shape outcomes.
Elayne Whyte-Gomez, former Ambassador and Permanent Representative of Costa Rica to the United Nations, Senior Fellow of the United Nation Institute for Disarmament Research, and Professor at Johns Hopkins School of Advanced International Studies.
The international order, Ambassador Whyte-Gomez argued, is not simply something that powerful states construct and destroy on their own terms. It is sustained by the willingness of the broader community of states to defend it, invoke it, and refuse to look the other way when it is violated. When small and middle powers invoke its norms, challenge violations, and insist on accountability, the order retains its functional weight even when the most powerful actors strain against it. When they go silent, or worse, retreat into vague diplomatic language designed to offend no one and commit to nothing, the order loses the constituency that gives it life. “The international order does not cease to exist by the actions or the narrative of powerful actors alone,” she said. “It ceases to exist when the rest, such as experts and middle and small nations, acquiesce.”
What concerned Ambassador Whyte-Gomez was precisely that pattern of acquiescence beginning to take hold. States that might otherwise serve as normative anchors are increasingly issuing statements carefully calibrated to avoid confrontation, offering wishy-washy expressions that say nothing. The pressure to accommodate is real and understandable, she acknowledged, but she drew a sharp distinction between principled restraint and silence. A state that chooses not to speak when the rules it has long championed are being dismantled is not staying neutral. It is making a choice, and that choice has consequences for the durability of the very framework it depends on.
Ambassador Whyte-Gomez then placed the current moment in a longer historical frame. She drew on two precedents where deliberate, advanced legal and political thinking produced institutions that shaped the international order for generations. The first was the preparatory work that preceded the Paris Peace Conference of 1919, as mentioned previously in this post, where Wilson and a team of advisors spent months drafting proposals for a post-war order before negotiations began, work that ultimately produced the blueprint for the League of Nations. The second was the drafting of the UN Charter in 1945, where the architects of the post-war order translated the lessons of catastrophic failure into a new framework for collective security and international law. In both cases, lawyers played a central role not as technicians implementing decisions already made by politicians, but as architects of the conceptual framework within which those decisions were made. “There is a role now for lawyers,” she said. “To stop and think.”
Ambassador Whyte-Gomez then returned to the historical arc that Ambassador Braithwaite had opened earlier in the session and brought it to a precise conclusion. Where Ambassador Braithwaite had traced the erosion of multilateral architecture across three decades of Western military interventions, Ambassador Whyte-Gomez identified what is categorically new about the present moment.
Throughout the post-war period, the United States, even when acting outside the bounds of international law, maintained the practice of constructing a legal justification for its use of force and formally communicating that justification to the UN Security Council, invoking the right to self-defense pursuant to Article 51 of the UN Charter. The justifications were sometimes thin and sometimes contested, but they existed, and their existence mattered, because they acknowledged the framework even in the act of straining against it. They provided other states with something to engage with and challenge; they openly conveyed a vision of the situation and a shared vocabulary through which other actors could understand it and hold power to account through a formal communication process.
The present difficulty in building a legal rationale is therefore not a minor procedural omission. Rather, it reveals a new context for the decision-making process and the standard inter-agency contributions. The policy process has become disarticulated from the framework itself, playing no role in the final decision. “This,” she concluded, “is the real rupture.”
Accountability, Institutions, and the Compliance Crisis
Kateryna Kyrychenko, Head of Ukraine Legal Affairs and Program Management at PILPG
Kyrychenko’s contribution reframed the institutional discussion in a way that cut against the grain of much of what had preceded it. “There is nothing inherently wrong with international law,” she argued. “The real problem lies in its execution and compliance.” She described what she called an age of “international populism,” a period in which international agreements are signed as political gestures, frequently rushed to meet symbolic deadlines or demonstrate quick diplomatic success, producing documents that are “difficult, if not impossible, to enforce.” The politicization of international law, in her diagnosis, consistently prevails over its genuine legalization.
Her prescription looked inward: greater attention to national legislation and constitutional frameworks. Wars are ultimately won by states, not international institutions, and the preservation of constitutional order is critically important. Ukraine, she argued, offers a powerful example: despite more than four years of full-scale aggression, the country has continued to uphold its constitutional regime, “an achievement that deserves recognition,” demonstrating how, in practice, domestic legal resilience becomes critical where international law cannot ensure compliance.
Stephanie Gusching, Associate at White & Case, secondee at PILPG
Gusching focused on the structural pathologies of the UN Security Council. The veto mechanism has rendered the Council functionally inoperative at precisely the moments it is most needed, including with respect to Ukraine, Gaza, and Iran. “If international law exists, we need to reimagine how these institutions operate and evolve,” she said. Her proposals are specific: majority-based consent structures within the Council and required abstention for parties directly implicated in a conflict. The world that produced the UN Charter in 1945 no longer exists; the institution designed for that world should not be expected to function as if it still does.
Middle Powers and the Question of What Comes Next
Dr. Williams posed the session’s most forward-looking question: when we come to this fork in the road, who chooses which way we go? Some will say the US. Some will say a new coalition of middle powers. Is it possible that both paths are pursued simultaneously, the US doubling down on a constricted definition of its interests while others construct an alternative architecture?
Ambassador Jorge Lomonaco, former Ambassador of Mexico to the UN Human Rights Council and to the Organization of American States
Ambassador Lomonaco articulated the middle power dilemma with the precision of someone who has spent decades navigating it from the inside. For much of the post-war period, he argued, middle powers had a clear orienting framework. They could look to a set of principles that were anchored in international law, multilateral cooperation, and the peaceful resolution of disputes, and align their foreign policy accordingly. That alignment was not always without tension, and the principles were not always perfectly applied, but the framework itself was coherent and the direction of travel was clear. What the current moment has disrupted is not simply the application of those principles but the willingness of the state that underwrote them to continue doing so. That leaves middle powers in genuinely uncharted territory. Aligning with a world order stripped of the principles that once gave it legitimacy is not an attractive option. Aligning with an alternative order built around spheres of influence and the primacy of force is equally untenable for states whose security and prosperity depend on rules that apply to everyone.
“What do we do as a middle power now?” he asked. The question, in his framing, is not rhetorical. It is the central strategic challenge facing a significant portion of the international community, and it does not yet have an answer. What it demands is the construction of a third path, one that does not yet exist but that middle powers may have both the incentive and the collective capacity to build.
Ambassador Julian Braithwaite, former British Ambassador to the WTO, UN, and Other International Organizations in Geneva.
Ambassador Braithwaite offered a candid counterweight to the more aspirational threads of the discussion. The history of international order, he argued, has never been one of genuinely collective governance. It has always been shaped by the interests and the power of the states willing and able to enforce its rules. That is a structural observation and it carries direct implications for what middle powers can realistically hope to achieve.
The Russian position, he noted, has been about a world organized around spheres of influence, where great powers exercise predominant authority within their respective regions and smaller states navigate their relationships with those powers accordingly. That model has deep historical roots, predating the post-1945 order and never fully displaced by it. The current US posture, in Ambassador Braithwaite’s reading, reflects a degree of comfort with that framework, a willingness to think about international relations in terms of deals, bilateral leverage, and zones of interest rather than universal rules and multilateral institutions. China, meanwhile, has been watching the erosion of the rules-based order with considerable strategic interest. A world in which the rules-based order weakens is not, from China’s perspective, an unambiguously unwelcome development. The space that opens as multilateral institutions atrophy is one in which bilateral leverage, economic coercion, and regional dominance become more consequential.
For middle powers, the challenge is that none of these trajectories leave an obvious role. A world organized around great power spheres of influence is precisely the world in which states that are too large to be ignored but too small to set the terms find themselves most exposed. “We need to be realistic,” he said, “about what rules-based order can be constructed on top of the ashes of this one.” The aspiration to build something better is necessary. But aspiration without a clear account of who will build it, on what foundation, and with what enforcement capacity is not architecture; it is hope.
Jason Steinbaum, Former Staff Director, Committee on Foreign Affairs, US House of Representatives
Steinbaum offered a perspective that resisted the session’s more pessimistic conclusions without dismissing them. “We may not be at a complete rupture,” he said, “but we can discern some things from the current actions. There is still a thirst for a rules-based order, for democracy, although it’s not in all corners.”
Steinbaum pointed to a debate that he argues is still very much alive within the US itself. The war powers framework, which governs the constitutional relationship between the executive branch and Congress over the use of military force abroad, has been stretched and strained repeatedly since its codification in the War Powers Resolution of 1973. Presidents of both parties have pushed its limits; Congress has oscillated between reasserting its authority and acquiescing to executive action. That tension is not resolved, and the question of who in the US constitutional system has the authority to commit the country to military action, and under what conditions, remains genuinely contested. His broader point was that the internal US debate about the country’s role in the world and the limits of executive power is unfinished. The outcome of that debate will have consequences that extend well beyond US borders, which is precisely why the international legal community has a stake in following it closely.
Conclusion
The urgency in this post’s contributions suggests that these are not merely academic questions. Dr. Crane states it plainly: “We are in an age of aggression, a corollary of the rise of the strongman, where the unilateral use of force outside the UN paradigm is becoming a norm.” The question then becomes whether we can live in a world where the UN does not matter.
The experts converge not on pessimism, but on a specific and actionable form of urgency. The rupture is real. The normative vocabulary is losing value. The institutions are atrophying. The middle powers face a choice between constructing an alternative architecture and acquiescing to a world ordered by spheres of influence.
But acquiescence, as Ambassador Whyte-Gomez reminds us, is a choice too, and it is the choice that will determine whether what has been broken can eventually be rebuilt. The working group’s consensus is that it cannot afford to be made by default. At historical inflection points, lawyers and practitioners can stop, think, and help construct the vocabulary for what comes next.