Russia’s invasion of Ukraine has prompted States, scholars, advocacy groups, and international institutions to consider the best way to hold leaders accountable for the crime of aggression. The approaches include creating international tribunals, hybrid tribunals, and national tribunals.

Those proposals have led to a lot of imprecise talk. To be clear: an international tribunal is one based directly on international law, established through the United Nations Security Council (which created the International Criminal Tribunals for the Former Yugoslavia and Rwanda, the ICTY and ICTR respectively), or created by bilateral agreement between the United Nations and a country (for instance the Special Court for Sierra Leone). Although the latter had hybrid features, its legal basis made it an international tribunal.

There may also be a hybrid tribunal formed through national law within a country’s national system, as was the Extraordinary Chambers in the Courts of Cambodia. This type of tribunal is better called a national tribunal with certain international features.

Last month, the United States announced its support for an “internationalized tribunal dedicated to prosecuting the crime of aggression against Ukraine.” But the U.S. proposal – and efforts to defend it – fail to address some key concerns: (1) the issue of immunities; (2) the weak precedential weight of a domestic tribunal; and (3) the issue of Constitutionality under Ukrainian law. Ultimately, an international tribunal is the better approach given the gravity of the crime of aggression and the future development of international criminal law.

An International Tribunal is Imperative

As I and other colleagues have previously explained, the form a tribunal takes – whether international or national – is quite significant when it comes to piercing the personal immunities of heads of States, heads of government, and ministers for foreign affairs (see this post by Astrid Reisinger Coracini and myself, and this post). In the former case (an international tribunal formed through the U.N. system) they would not apply; but in the case of a national institution, they would shield such a defendant from prosecution.

This is a significant reason why President Zelenskyy has endorsed the creation of an international tribunal on the crime of aggression – the Special Tribunal on the Crime of Aggression (STCoA) – established through the United Nations. In fact, Zelenskyy’s Office has publicly stated that the idea of creating a “hybrid tribunal” as an instrument for investigating the crime of aggression committed by the Russian Federation is “unacceptable.”  For a leadership crime (as the crime of aggression is, see Rome Statute Art. 8bis) a prosecutor would ideally investigate and charge all those leaders who participated in the decision to initiate an act of aggression, beginning with the top political leaders. In the case of Russia’s war on Ukraine President Putin is the tip of the Kremlin’s spear.

Along with personal immunities, a court within the Ukrainian national system also faces serious Ukrainian constitutional impediments (see this piece by Oona Hathaway and Alexander Komarov).

Moreover, from the perspective of the future of the international legal order, it is of cardinal importance that faced with Russia’s fundamental assault on the prohibition of the use of force, the international community as a whole puts thegreatest possible weight behind the judicial precedent against aggression. That would not happen if a special tribunal were essentially national in character.

As I previously wrote, the warrants of a tribunal formed within a national system and judgments of such a tribunal will never be seen to carry nearly the weight of those of an international institution applying international law and presided over by international judges. The rulings of Ukrainian judges could be dismissed as lacking in impartiality or – even if impeccably well-reasoned – lacking the appearance of impartiality. These difficulties would only be exacerbated if trials are conducted in absentia, as Ukrainian law allows (see the Criminal Procedural Code of Ukraine, art. 7.2).

The U.S. Proposal of a National Court

Recently, the dialog seems to have shifted from calling for a “hybrid tribunal” (see the U.K.’s earlier announcement), to an “internationalized” national court. This is evident in both the U.S. proposal pronounced by Ambassador Beth Van Schaack and a recent post by Michael Scharf, Paul Williams, Milena Sterio and Yvonne Dutton of the Public International Law and Policy Group, (PILPG).

On Mar. 27, Ambassador Van Schaack announced U.S. support for an “internationalized tribunal dedicated to prosecuting the crime of aggression against Ukraine.”

Admittedly, having the U.S. agree that “there are compelling arguments” for why the crime of aggression must be prosecuted (see Van Schaack’s remarks), is a step in the right direction, but, regrettably that is the only step.

Unfortunately, what the United States endorses is a Ukrainian court “rooted in Ukraine’s judicial system.”  And while Ambassador Van Schaack did mention “international elements” in terms of “substantive law, personnel, information sources, and structure” of the proposed tribunal, the U.S. approach failed to address: (1) the issue of immunities; (2) the weak precedential weight of a domestic tribunal; and (3) the issue of Constitutionality. (See Rebecca Hamilton’s critiqueof the U.S. plan).

PILPG’s Defense of a National Approach

PILPG’s recent post applaud the U.S. proposal, suggesting that the impediments under the Ukraine’s Constitution are surmountable, for instance, through substituting “international advisors” for international judges. But this is an even weaker international features of the proposed national tribunal than what the United States called for, as it would basically create an entirely domestic court.

Here is the Catch-22: a significantly new tribunal within the Ukrainian system will run into Constitutionality impediments. In flawed logic, the PILPG authors suggest that because some kind of hybridized or national tribunal was created within the national systems in Iraq, Kosovo, Serbia and Bosnia, there is no impediment to creating a similar tribunal within the Ukrainian system. Whatever the Constitutions of Iraq, Kosovo, Serbia or Bosnia may or may not have permitted is quite irrelevant – the issue here concerns Ukraine’s Constitution (which prohibits “special” or “extraordinary” Chambers being created within the Ukrainian court system as well as the use of non-Ukrainian judges).

As for immunities, PILPG attempts to side-step the issue. Its post admits that personal immunities do attach, but suggests that prosecutions of those a level or two down from the top level leaders are possible. That is true in terms of the leadership element of the crime of aggression. But for a crime that is necessarily committed with participation at the top leadership level, it poses a fundamental problem of legitimacy that cannot, and should not, be so easily dismissed. PILPG’s approach suggests that one should effectively exonerate, for instance, the commander-in-chief who made the decision to launch an illegal war so their subordinates can take the blame for that choice. Moreover, the Ukrainian Government has specifically rejected an approach that would entail such immunities.

Equally untested and potentially legally unsound is another PILPG workaround to the immunity problem. It suggests to first create a tribunal within the Ukrainian system, and then later obtain a United Nations General Assembly (UNGA) endorsement once the court is established. We have absolutely no idea if that would work. While UNGA endorsement would mean the tribunal would be endorsed by the international community as a whole, the tribunal would not be createdunder international law. Both are required to safely avoid personal immunities from attaching. (See Reisinger Coracini and Trahan).

Finally, in advocating for the use of international advisors to circumvent the Constitutionality impediment, PILPG raises the model of the Iraqi High Tribunal. But instead of supporting PILPG’s position, that tribunal provides a clear warning lesson why the international community should be wary of domestic courts with a bit of hybridity. Despite international definitions of the crimes, international funding, international assistance by the United States Regime Crimes Liaison Office in Baghdad, and international advisers, the Iraqi High Tribunal, which was an Iraqi court created under Iraqi law, was never seen as legitimate. The bench was composed of Shiite and Kurdish judges trying their deposed Sunni leader, Saddam Hussein. Executions followed in quick order despite a panoply of fair trial violations at trial and a complete sham of an appeals process. See Trahan here (fair trial violations during the IHT’s Dujail trial); see also here (fair trial violations during the IHT’s Anfal trial).

Moreover, the PILPG post has done no analysis of how well a domestic Ukrainian court with international advisers is likely to work and what kind of precedent (or lack of precedent) it is likely to set. Those are questions worth unpacking. Ignoring them risks a similarly weak tribunal for the crime of aggression in Ukraine.

Why Debate Weak Tribunal Proposals?

All of this begs the question of why we are even debating a national court within the Ukrainian system with some international elements that could not prosecute the very top leaders who gave the authorization to commit the crime of aggression and the judgments of which would fail to carry the badly needed authoritative weight of an international tribunal established by a treaty between the U.N. and Ukraine.

On the eve of the 20th anniversary of the invasion of Iraq, one might wonder whether something else is occurring when the U.K. (which earlier proposed a hybrid tribunal within the Ukrainian system) and now the United States (with Ambassador Van Schaak’s approach) propose a weak tribunal to prosecute the crime of aggression. How convenient it is to call for justice, but self-servingly create a weak precedent that avoids setting international precedent for the future.

Top Leaders Should Not Escape the Rule of Law While in Office

Some have asked – in effect: why worry so much about head of State immunity, given Putin is likely to be tried only once out of power? (See Kevin Jon Heller’s post).

When it comes to doing the right thing and pursuing the rule of law, the form a tribunal takes should not dictate its ability to function: the very leaders that initiated the crime must not be automatically exempted simply by endorsing a weak tribunal model where those leaders would have personal immunity.

It is indeed unlikely that Putin will appear in The Hague while he is still in power, but he could be indicted for the crime of aggression (which would not be possible at an internationalized tribunal established under national law). An international court issuing charges for the crime of aggression would send a powerful deterrent message to world leaders about the unacceptability of brazenly invading a neighboring State. To have the highest Russian leaders indicted for the crime of aggression is exactly the deterrent message that needs to be sent (not to mention, the cost of establishing the STCoA would be a mere drop in the bucket compared, for example, to the cost of coming to the military assistance of yet another victim state).

Conversely, to establish a tribunal within the Ukrainian system (as the U.K. and U.S. models propose) that is unable to even proceed against the entire top Russian leadership sends exactly the wrong message that leaders are above the rule of law while they remain in power. And, even then, after they have left power, they would not need to face justice for the crime of aggression at the international level.

After we have made so much headway in prosecuting genocide, war crimes and crimes against humanity at the international level, we must get serious also about prosecuting the crime of aggression as a crime under international law. All of the harm that has been inflicted upon Ukraine through the 2022 invasion (and 2014 before that) shows why it is time to stop putting the crime of aggression on a lesser tier than the ICC’s other crimes.

Being on the Right Side of History 

States that wish to support both Ukraine and the international legal order need to be on the right side of history – as so many were in pressing for a broad ICC jurisdictional regime over the crime in both negotiations in Kampala and at the 2017 ASP session where the ICC’s jurisdiction over the crime was activated (for the negotiations, see here and here).

They need to unite behind President Zelenskyy’s call for a STCoA to be created through UNGA. (See also FAQ). This is acknowledged to be the most credible route to truly enforce the foundational provision against aggressive use of force found in Article 2(4) of the U.N. Charter and deter future uses of aggressive force. (See Hans Corell’s post on steps for creating the tribunal. Contrary to some suggestions (see Heller), there is nothing that says the STCoA must be created with “overwhelming UNGA endorsement” to avoid immunities; if the General Assembly vote passes, the General Assembly vote passes).

Yes, an ad hoc approach is imperfect, and that is why, as a second step, states will need to revise the Kampala amendment’s jurisdictional regime and broaden the ICC’s jurisdiction over the crime so that it may investigate and prosecute the crime in future. (See these statements by the Global Institute for the Prevention of Aggression, GIPA, and the Parliamentarians for Global Action, PGA).

States from all regions of the globe – particularly ones that have suffered historically from colonialism, imperialism, and annexation need to come together to ensure application of the rule of law and firmly establish the unacceptability of brazenly invading a neighboring State – but they need to do so through a legitimate, U.N.-backed tribunal. States should not sit back and make the mistake of thinking these issues are only ones for NATO member State or European nations, or in being complacent setting weak precedent. No State, from any region, including island nations, is safe if blatant aggression is permitted to go unchecked. Unequivocal precedent must be set, both through the creation of the STCoA and eventual amendment of the ICC’s Rome Statute to broaden the Court’s jurisdiction over the crime of aggression. Global stability and the rule of law demands no less.

IMAGE: From left, Ambassador-at-Large for Global Criminal Justice Beth Van Schaack, State Department interim spokesman Vedant Patel, Acting Assistant Secretary, Bureau of Democracy, Human Rights, and Labor, and Coordinator for Global Democratic Renewal Under Secretary for Civilian Security, Democracy, and Human Rights Erin Barclay, listens as Secretary of State Antony Blinken speaks at a briefing on the 2022 Country Reports on Human Rights Practices at the State Department in Washington, Monday, March 20, 2023. (AP Photo/Andrew Harnik)