I had the pleasure of participating in an Interactive Panel Discussion on the crime of aggression at the United Nations yesterday on the occasion of International Justice Day (so named because it marks the final day of the Rome Conference convened to establish the International Criminal Court (ICC)). On the panel with me were:

The panel, entitled “Into the homestretch: towards the activation of the Kampala Amendments on the crime of aggression” and organized by Liechtenstein, was dedicated to the consideration of the crime of aggression, which is slated to be added to the Statute of the International Criminal Court at some point after January 1, 2017, following a decision to that effect of the ICC’s Assembly of States Parties.

Status of Ratifications

The aggression amendments require 30 State Party ratifications before they can be activated, no earlier than January 1, 2017. Liechtenstein was the first to ratify the amendments on May 8, 2012. Prior to today, thirteen additional states had followed suit: Bosnia-Herzegovina, Belgium, Botswana, Croatia, Cyprus, Estonia, Germany, Luxembourg, Samoa, Slovakia, Slovenia, Trinidad & Tobago, and Uruguay. Austria announced its ratification at the event, bringing the necessary ratifications to the halfway point.

Given events in Crimea, it is perhaps not surprising that Eastern Europe is in the lead regionally, and Albania, the Czech Republic, Georgia, Macedonia (FYROM), and Poland have indicated an intention to ratify by the end of the year. Seven NATO members have ratified the amendments to date (Belgium, Croatia, Germany, Estonia, Luxembourg, Slovakia, and Slovenia); others have indicated an intention to do so as have NATO aspirants Moldova, Macedonia, and Georgia. (Spain was originally slated to announce its ratification yesterday afternoon, but parliamentary delays intervened). The European Parliament has called on member states to ratify and domestically incorporate the amendments, most recently with s resolution dated July 16, 2014. Outside of Europe, the Asia-Pacific and Africa regions have also played host to workshops on ratification and implementation, although ratifications have not been forthcoming. Japan’s new interpretation of its Constitution—permitting its Self-Defense Forces to be deployed in collective self-defense—comes just as Japan announced that it is in the early stages of ratification. A handful of these states (e.g., Slovenia (Article 103), Croatia (Article 89), Ecuador (Article 88)) have incorporated the crime of aggression into their domestic penal codes as part of the ratification process, although this is not required.

A Note of Caution

My role on the panel was to inject a note of caution regarding the activation of the aggression amendments and to suggest ways to address persistent ambiguities in the amendment package as well as potential negative consequences to international peace and justice. The main thrust of my remarks appears below the fold.

The decision in Kampala by the ICC’s Assembly of States Parties to defer the exercise of jurisdiction over the crime of aggression (see Article 15bis/ter (2)(3)) was a wise one. Significant work remains to be done to prepare the Court to take on this new, controversial, and challenging crime. From the perspective of the Court itself—its various organs, its staff, its program of work—this postponement will give the institution time to consolidate its work on its existing cases, which remain fragile. This involves:

• commencing and concluding trials on its current indictments, which charge crimes that deserve the Court’s full attention,

• improving its efficiencies and increasing its pace of work,

• continuing to resolve a number of procedural bugs and questions of first impression that have emerged as the Court has endeavored to operationalize its statute, and

• improving mechanisms of state cooperation, making progress on executing outstanding arrest warrants, and thinking creatively about new solutions to the problem of long-term fugitives.

This postponement will also allow the Court time to prepare to make any adjustments to its organizational structure, personnel mix, allocation of resources, etc. necessary for the effective prosecution of this new, qualitatively different, and potentially highly political crime.

From the perspective of those of us outside the Court—but part of an international community devoted to the system of international criminal justice—events like this one reveal that this period of postponement is being put to good use. In particular, notwithstanding the illusion of consensus in Kampala, sharp disagreements remain as to what the various statutory amendments actually mean. Some of these ambiguities were apparent at Kampala—when there was quite simply insufficient time to address all the complexities presented by the inclusion of the crime of aggression into the Statute (such as how complementarity should operate or the timing of the opt out clause)—whereas others have materialized since that time (particularly concerning the most fundamental of issues: how precisely the amendments will be activated). As we progress toward 2017, it is important for friends of the Court to reach greater clarity on these issues, so that they are not dumped on the laps of the judges in the context of a live case involving a defendant entitled to be prosecuted according to a regime that satisfies the principle of legality. The credibility and fairness of the Court depend on states parties and observer states doing the responsible thing now before 2017.

Lingering Definitional Questions

The definition of the crime of aggression was largely complete by the time of the Kampala Conference in 2010. Article 8bis reads:

For the purpose of this Statute, “crime of aggression” means the planning, preparation, initiation or execution, by a person in a position effectively to exercise control over or to direct the political or military action of a State, of an act of aggression which, by its character, gravity and scale, constitutes a manifest violation of the Charter of the United Nations.

“Act of Aggression” is separately defined as:

For the purpose of paragraph 1, “act of aggression” means the use of armed force by a State against the sovereignty, territorial integrity or political independence of another State, or in any other manner inconsistent with the Charter of the United Nations.

These definitions are followed by a list of exemplary aggressive acts drawn from General Assembly Resolution 3314, promulgated in 1974 to guide the Security Council in making aggression determinations. Delegates also adopted a series of Understandings in connection with the amendments, two of which address definitional issues:

6. It is understood that aggression is the most serious and dangerous form of the illegal use of force; and that a determination whether an act of aggression has been committed requires consideration of all the circumstances of each particular case, including the gravity of the acts concerned and their consequences, in accordance with the Charter of the United Nations.

7. It is understood that in establishing whether an act of aggression constitutes a manifest violation of the Charter of the United Nations, the three components of character, gravity and scale must be sufficient to justify a “manifest” determination. No one component can be significant enough to satisfy the manifest standard by itself.

Obviously, much hinges on the term “manifest” in this definition. Although statements in the amendments’ travaux préparatoires and the academic literature insist that the amendment’s text, the Understandings, and the term “manifest” would all exclude borderline cases and so-called “grey areas”—such as situations of insufficient gravity or cases in which a use of force was not undertaken for aggressive purposes—it would be helpful for these supposedly shared conclusions to be spelled out more concretely before the aggression amendments are activated.

Responsibility to Protect

Most importantly, advocates for the Responsibility to Protect and the imperative of atrocities prevention should be at the front lines in ensuring that the aggression amendments do not over-deter or otherwise hinder the deployment of armed force to prevent the commission of other Rome Statute crimes—genocide, crimes against humanity, and war crimes. Although the most pointed proposals to exempt such humanitarian actions were not adopted in Kampala, the amendments and the Understandings should be interpreted to exempt bona fide humanitarian interventions from prosecution as the crime of aggression.

Without greater certainty that the definition of aggression does not include humanitarian actions, ambiguities inherent to the definition of the crime of aggression, coupled with the checkerboard jurisdictional regime and the unequal threat of prosecution among states and states parties, may impede coalition-building and other multilateral responses to global threats.  State legal advisers will no doubt have differential tolerances for the degree of uncertainty inherent to the reach of the aggression amendments. The concomitant difficulty in mobilising joint action may paradoxically lead to more unilateral actions by states not subject to the aggression amendments. Thus, the existence of the crime on the books may ultimately make multilateral action in the face of mass atrocities more difficult.

To be sure, the legality and legitimacy of humanitarian intervention remain unsettled in positive law, and contradictory pronouncements on whether such actions are appropriate in the absence of Security Council approval have emerged from authoritative elements of the international community. However, it is precisely because this is an area of legal uncertainty that the Court should be directed to avoid aggression charges when states are motivated by humanitarian concerns. More can thus be done in the run up to 2017 to preserve some space to develop the third pillar of the R2P doctrine, which focuses on coercive actions, including uses of military force.

One option would be to further explore how the “defense of others” (Article 31(1)(c)) might serve as a defense to a charge of aggression in a humanitarian context. That defense applies when:

The person acts reasonably to defend himself or herself or another person … against an imminent and unlawful use of force in a manner proportionate to the degree of danger to the person or the other person or property protected. The fact that the person was involved in a defensive operation conducted by forces shall not in itself constitute a ground for excluding criminal responsibility under this subparagraph…

Another options would be to tinker with the mens rea associated with the crime of aggression in the draft Elements of Crimes or elsewhere. In particular, the Court could be directed to expressly consider the state’s “purpose” in resorting to armed force and identify exemplary prohibited purposes, such as conquest, establishing a military occupation in the victim state, launching a war of aggression, achieving the annexation of the other state’s territory, acquiring the other state’s material resources, undermining the political independence of the state, or violating a state’s neutrality. Or, aggression could be conceived of as a specific intent crime.

Such stipulations would provide a firmer textual basis for distinguishing bona fide from pretextual humanitarian interventions. While huge swaths of the globe remain under threat of mass atrocities, we should not foreclose the ability to develop a principled yet cautious doctrine of humanitarian intervention in the event of Security Council paralysis or inaction, as we have seen in Syria.


Very little attention was paid to the principle of complementarity during the negotiations surrounding the crime of aggression. The ILC in its original draft of a statute for a permanent international criminal court actually contemplated vesting exclusive jurisdiction over the crime of aggression in the international court then under contemplation (with shared jurisdiction over the atrocity crimes). There was a wisdom to this original approach that should not be forgotten.

There is no treaty-based obligation to incorporate the crime of aggression into states parties’ domestic criminal codes. Indeed, the Understandings adopted in connection with the aggression amendments express a subtle preference that states not incorporate the crime of aggression into their penal codes or launch domestic prosecutions for the crime. This is prudent, given that domestic prosecutions for the crime of aggression can

  • generate intense charges of politicization from within and outside the prosecuting state,
  • exacerbate international relations, and
  • complicate—or even derail—bilateral or multilateral efforts to achieve a diplomatic resolution to a dispute that has involved a resort to armed force.

If states parties do choose to incorporate the crime into their domestic codes, they should guard against the fragmentation of the law. Thus, any domestic definitions should hew closely to aggression amendments in terms of definition and elements and specifically incorporate the Understandings alongside the terms of Article 8bis. Domestic legislators should also consider:

  • limiting prosecutions to their own nationals pursuant to the nationality principle of jurisdiction, as draft legislation in New Zealand would have done, or
  • limiting prosecutions to those situations in which the Security Council has declared the commission of an act of aggression by the defendant’s state of nationality.

A Way Forward

Although the Kampala Conference is behind us, it is not too late to address these concerns in advance of 2017. When states parties ratify the amendments, they should be sure to indicate that they consider the Understandings to be an integral part of the aggression amendments. These understandings should be incorporated in domestic ratification resolutions as well as the instruments of deposit submitted to the U.N. Secretary General. Although the Rome Statute disallows Reservations per se at Article 120, nothing prevents states parties from ratifying the amendments with Understandings and Declarations.

States parties should also consider utilizing the option of a partial opt out declaration anticipated by Article 15bis(4) to indicate that it is accepting the amendments except with respect to their involvement in military actions undertaken in order to prevent the commission of other Rome Statute crimes. In other words, the state could indicate that it does not accept the jurisdiction of the Court with respect to genuine humanitarian interventions or operations undertaken pursuant to the Responsibility to Protect.

The necessity of the ASP making an affirmative “decision” to activate the aggression amendments in 2017 offers states parties and other friends of the Court a chance to collectively address some of these lingering issues. That decision need not involve an unreflective “yes or no” vote; rather, states parties should issue a substantive resolution in connection with the activation decision to elaborate on the Kampala package in order to

  • Clarify that military action to prevent the commission of other Rome Statute crimes is not a “manifest” violation of the Charter;
  • Assert that the defense of others outlined in Article 31(1)(c) would apply to the determination of whether an act of aggression had been committed by a state or the crime of aggression had been committed by an individual.
  • Affirm the centrality of the Understandings to the definition of the crime as a primary means of interpretation within the lexicon of the Vienna Convention on the Law of Treaties; and
  • Confirm that to the extent that aggression prosecutions do go forward, it is preferable for them to go forward before the ICC rather than in domestic courts.

Ensuring greater clarity and consensus on these issues will only enhance the durability and palatability of the Kampala amendments. The next President of the ASP, whomever it may be, should structure the activation process in such a way as to solidify these outstanding issues so that they are not simply dumped in the laps of the judges when the first aggression case arrives at the Court.


All of us—representing states parties and non-parties alike—must work together to ensure that the codification of the crime of aggression

  • strengthens—rather than de-stabilizes or over-taxes—the Court;
  • improves—rather than weakens—the Court’s relations with states (both parties and non-parties) and with the relevant organs of the international system;
  • brings states together under the umbrella of international justice rather than drives them apart;
  • enhances—rather than undermines—prospects for state cooperation, particularly from powerful states; and
  • contributes to greater order—rather than disorder—in international relations.

It would be a great tragedy if case involving charges of aggression shattered the broad-based political support now enjoyed by the Court or if the political complexities of an aggression prosecution distracted the Court from its core agenda, which is to adjudicate atrocity crimes afflicting victims the world over.