Across the past eight decades, the international community has experienced successive “waves” of atrocity accountability—periods in which global norms either strengthened or eroded in the face of mass violence, authoritarian resurgence, and geopolitical disruption. Today, the world stands at the threshold of a fourth wave: the Age of Aggression, a moment defined by the collapse of long-standing restraints, the rise of strongman politics, and the open defiance of the United Nations Charter by powerful states—including the United States itself. This article outlines the four waves of accountability, analyzes their significance, and assesses the grave implications of a world in which aggression is once again normalized as a tool of statecraft.
Wave I: Nuremberg and the Birth of Modern Accountability
The first wave began in 1945 with the International Military Tribunal at Nuremberg. For the first time in history, leaders were held criminally responsible for waging aggressive war and orchestrating atrocities. Nuremberg established three foundational principles:
- Individual criminal responsibility for international crimes, including crimes against humanity and the crime of aggression.
- The rejection of impunity for heads of state, a revolutionary concept at the time.
- The articulation of a rules‑based international order, grounded in the UN Charter and the promise of “never again.”
Nuremberg created the legal and moral architecture for modern international criminal law. It was the first great wave of accountability—a moment when the world believed law could restrain power.
Wave II: The Age of Accountability (1990s–2010s)
The post-Cold War era ushered in a renewed commitment to justice. The atrocities in the Balkans and Rwanda shocked the conscience of the world and led to the creation of the ICTY and ICTR. This period also saw:
- The establishment of hybrid tribunals, including the Special Court for Sierra Leone, which indicted a sitting head of state for the first time since Nuremberg.
- The creation of the International Criminal Court, a permanent institution intended to deter future atrocities.
- A global movement toward universal jurisdiction, truth commissions, and domestic accountability mechanisms.
This second wave was marked by optimism—a belief that law could be institutionalized, that accountability could be normalized, and that the international community could respond collectively to mass atrocity.
Wave III: The Age of the Strongman
Beginning in the 2010s, the world entered a darker period. Authoritarian leaders consolidated power, democratic norms eroded, and the international system fractured. This third wave is defined by:
- The resurgence of strongman rule, from Russia to China to Turkey to the Philippines.
- The deliberate weakening of multilateral institutions, including the UN Security Council.
- The normalization of disinformation, repression, and political violence as tools of governance.
- The paralysis of the international justice system, unable to act against powerful states.
This wave represents a direct challenge to the gains of the previous decades. Strongmen reject accountability as a threat to their survival. They view international law not as a constraint but as an obstacle to be dismantled.
Wave IV: The Age of Aggression
The fourth wave is not separate from the third—it is its logical extension. It is the moment when strongman politics metastasizes into open aggression, when the restraints of the UN Charter are cast aside, and when powerful states embrace force as a primary instrument of foreign policy.
For eighty years, the UN Charter’s prohibition on the use of force has been the cornerstone of global stability. That paradigm is now under direct assault. Under the current administration, the US has abandoned multilateralism in favor of a nation-centric foreign policy, asserting dominance in the Western Hemisphere through coercive military posturing toward Venezuela, Cuba, and even Greenland. It has signaled to the world that great powers may act unilaterally, without legal justification or international support.
When one of the world’s most powerful member states disregards the Charter, it sends a message: the rules no longer apply. We—the community of nations—no longer settle our disputes peacefully.
Strongmen elsewhere are watching—and learning. If the United States uses force to impose its will, why should others refrain? Russia’s aggression against Ukraine becomes easier to justify when the US itself disregards the prohibition on force. Regional powers may feel emboldened to settle disputes militarily, claiming precedent. The Security Council becomes irrelevant, unable to restrain its own permanent members. The Age of Aggression is not merely a geopolitical shift—it is a normative collapse.
The fourth wave signals a reversion to a world where might makes right; where borders are redrawn by force; where international law is seen as optional; and where atrocity becomes a tool of statecraft.
This is the antithesis of the post‑1945 order. It augurs a dark 21st century in which the protections built over decades are dismantled in a matter of years.
Implications for the Future
The Age of Aggression threatens to unleash a cascade of consequences. These could include increased frequency of interstate conflict, as norms erode and deterrence collapses; greater risk of mass atrocities, as strongmen use violence to consolidate power; the weakening of global governance, leaving crises unmanaged and populations unprotected; and/or a legitimacy crisis for international criminal law, which cannot function in the absence of state cooperation
If this wave continues unchecked, the world may face a century defined not by accountability but by impunity.
Conclusion: The Need for a Fifth Wave
The first four waves show a clear trajectory: from hope to erosion to collapse. The challenge now is to imagine—and build—a fifth wave. The tools exist: the ICC’s activated jurisdiction over aggression, the ongoing efforts to establish a Special Tribunal for Ukraine, and the resilience of civil society networks that continue to document atrocities even when courts cannot act. What is needed is the political will to wield them. A fifth wave would require:
- A renewed commitment to the UN Charter
- A strengthened system for prosecuting aggression
- A global coalition willing to confront strongmen
- A revitalized belief that law can restrain power
The Age of Aggression is not inevitable or final. But reversing it will require courage, leadership, and a recommitment to the principles first articulated at Nuremberg. The stakes could not be higher. The 21st century will be shaped by whether the world chooses accountability—or accepts atrocity as the new normal.
David M. Crane is a global leader in international criminal justice and the founding Chief Prosecutor of the UN Special Court for Sierra Leone. He has spent decades shaping accountability mechanisms around the world, including serving as a driving architect behind the Special Tribunal for the Crime of Aggression against Ukraine. Crane is a distinguished scholar of international law, a former senior US national security official, and a leading voice on the rule of law, state responsibility, and the legal limits on the use of force.
