A Reminder of the Importance of the Crime of Aggression: Considering the Situation of Russia and Ukraine

[Jennifer Trahan is Convenor at The Global Institute for the Prevention of Aggression and Clinical Professor at NYU Center for Global Affairs. Trahan was a member of the Council of Advisers on the Application of the Rome Statute of the International Criminal Court to Cyberwarfare.]

With Russian forces poised on the border of Ukraine and the US Government reportedly considering a major troop deployment to Eastern Europe, there could hardly be a starker reminder of the importance of the crime of aggression.  This crime may be prosecuted before the International Criminal Court or before the domestic courts of countries that have implemented the crime into domestic law (approximately 40), including Ukraine.  Of these, approximately 20 countries have “universal jurisdiction” related to aggression, and some countries, such as Ukraine, permit trials in absentia.

The idea behind the crime of aggression is simple:  enforce the UN Charter.  The Charter prohibits aggressive use of force in Article 2(4) subject to exceptions for “self-defense” under Article 51 and UN Security Council authorized interventions under Chapter VII.  Russian aggression into Ukraine would fall under neither exception.  While there are informal ways to try to “enforce” international law, for example, through economic sanctions, a cursory glance at the situation of Crimea, a victim of earlier Russian annexation, reveals that sanctions are not always capable of changing state behavior.

While the crime of aggression (i.e., “crimes against peace”) were prosecuted already in 1945-46 before the International Military Tribunal at Nuremberg, the crime was added late to the International Criminal Court’s Rome Statute, in negotiations held after the Court was already operational and able to prosecute its other “core” crimes—genocide, crimes against humanity, and war crimes.  In 2017, States Parties to the ICC’s Rome Statute took the decision to activate the crime, effective July 17, 2018. 

The ICC’s crime of aggression is also, admittedly, imperfect.  It requires both a “manifest” UN Charter violation (which has both pros and cons), and clearly suffers from a weakened jurisdictional regime.  In terms of the “manifest” Charter violation (measured by its “character, gravity and scale”) (Rome Statute, Art. 8bis, para. 1), this ensures that, for example, “minor border incursions” would not be prosecuted.  Yet, as President Biden’s gaff suggesting tolerance for “minor incursions” reminds us, such incursions could open the door to major ones and even a “minor incursion” may violate Article 2(4)’s prohibition on aggressive use of force.  

The recent cyberattack on government websites in Ukraine serve as an additional reminder that, today, “warfare” can take the form of conventional operations, cyber operations, or a “blended” attack consisting of both.  Contrary to some suggestions (see Politico), hybrid attacks can be part of military aggression and there is no lack of legal framework governing them.  Cyber is simply another weapon in the toolbox of states (and non-state actors).  The recent cyberattacks on Ukraine, standing by themselves, probably do not rise to the level of an “armed attack,” but cyber operations or “blended” operations are not in a law-free zone.  They are governed by the same laws as conventional military operations (see Tallinn Manual 2.0) and other areas of public international law.  (See “The Council of Advisers’ Report on the Application of the Rome Statute of the International Criminal Court to Cyberwarfare,” explaining when a cyber-operation could fall under the definition of each of the Rome Statute’s four crimes; see also Trahan).

As to jurisdiction, the ICC crime of aggression is not subject to the same jurisdictional regime as the remainder of the ICC’s crimes but is subject to additional exclusions from jurisdiction.  For example, the nationals of non-States Parties (which would include Russian nationals) are complete excluded from jurisdiction for purposes of State Party referrals and the Prosecutor acting proprio motu.  (Rome Statute, Art. 15bis).  The only other way a crime of aggression case can reach the ICC is through UN Security Council referral (Rome Statute, Art. 15ter), which obviously will not happen where a permanent member of the Security Council, such as Russia, is involved and able to veto referral.  (For the harms of vetoes, see Trahan.)

Yet, before a country that is not subject to ICC jurisdiction regarding the crime of aggression becomes too complacent, it is worth noting that approximately 15 countries have implemented the ICC crime of aggression into their domestic criminal codes (see five such laws here; see also here).  And, a couple dozen additional countries already had the crime incorporated into their domestic laws based on the Nuremberg Charter’s formulation of “crimes against peace” (see Reisinger-Coracini; see also here).

Significantly, Ukraine is one of the countries that has such a domestic crime of aggression law.  And, it has fairly recently utilized it in prosecuting former Ukrainian President Viktor Yanukovych as well as two Russian service members, Alexander Alexandrov and Yevgeny Yerofeyev.  According to scholar Sergey Sayapin, the service members’ trial was “arguably the first criminal trial on charges of aggression since the trials following from the International Military Tribunal in Nuremberg.”  Victor Yanukovych was indicted with complicity in launching a war of aggression against Ukraine.  (Id. and Sayapin here.)  This is not to say that major Russian political or military leaders will end up in a Ukrainian jail, but it is a reminder that the nationals of no country are above the law.  

Can such laws currently deter Russian aggression?  Probably not.  As mentioned, Russia is exempt from ICC jurisdiction absent the exceedingly unlikely event of a Security Council referral and Ukraine’s domestic aggression law probably will not create deterrence either.

Thus, the current situation both highlights the extreme importance of the crime of aggression and the need for the law to go further than it currently does.  For the crime of aggression to have more potential for deterrence: 

(a) the ICC Prosecutor should investigate and prosecute the crime when an appropriate situation arises in which the ICC has jurisdiction: 

(b) the Prosecutor should highlight the visibility of the crime, for instance, by issuing a policy paper on it or its gravity threshold, and mentioning it more regularly in press briefings and speeches; 

(c) more countries should ratify the crime of aggression amendment to the Rome Statute (or ratify the amended Rome Statute), and implement the crime into their domestic criminal codes; and

(d) eventually, States Parties to the Rome Statute in a future review conference or meeting of the Assembly of States Parties should consider whether they want to continue to have the “manifest” qualifier (which excuses “small” acts of aggression/ minor border incursions), and must revisit the jurisdictional regime, eliminating some of the carve-outs that exist and which weaken the potential for deterrence. 

It is worth remember that there was a time when Russia, the United States, the United Kingdom, and France stood united at Nuremberg in prosecuting this supreme crime.  The Kampala crime of aggression amendment has only achieved some of what these prosecutions stood for.  States now need to again be united in standing behind and enforcing the UN Charter.