Reports of a possible Russia-Ukraine peace agreement continue to bubble and churn. The latest is an apparent Russian rejection of a peace plan floated by the Trump transition team. Uncertainty over the specifics of an agreement is likely to continue at least until the new administration takes office. But potential provisions are almost certainly being vetted in foreign ministries around the world. In a recent EJIL Talk post, Philipp Kehl ably addresses issues surrounding territorial transfers that would likely be at the heart of any agreement.
In this post, I would like to expand on points Kehl made regarding territorial change and address three additional issues: the reasons for the substantial legal uncertainty surrounding an agreement, potential provisions other than those concerned with the transfer of territory, and the potential role of the UN Security Council in “curing” any legal defects in an agreement. I will assume the reader’s familiarity with Russia’s occupation of Crimea and the Donetsk and Luhansk regions of Ukraine.
I will also assume that any agreement will have as parties not only Russia and Ukraine but other states that have been assisting both sides. Some rules of treaty law applicable to a potential peace agreement differ depending on whether a treaty is bilateral or multilateral.
Finding the “law” of Peace Agreements
Despite innovative scholarship seeking to create a unified legal theory of contemporary peace agreements (such as Christine Bell’s lex pacificatoria and Carsten Stahn’s jus post bellum), contemporary international law does not contain a stand-alone set of doctrines addressing peace agreements. This was not always the case. In the pre-Charter era, peace agreements were a central concern of the “law of war,” since they demarcated the formal end of that specific body of rules applicable only in times of armed conflict and the return to normal rules of peacetime. I have described peace treaties of that era as performing a “signaling function,” notifying the international community that, for example, the law of neutrality, the suspension of regular treaty relations, and the possibility of recovering captured property had come to an end. As Marko Milanovic summarizes, “[s]ince ‘war’ was a formal business, it also needed to be formally terminated.”
There are several reasons why this body of law has effectively fallen into desuetude and why contemporary international law has very little to say about peace treaties as such (the U.S. Department of Defense Law of War Manual, for example, newly updated in July 2023, devotes only 2 pages to the termination of hostilities). First, most conflicts today are non-international (NIACs) and the number of agreements ending international armed conflicts (IACs) has radically declined. The PA-X dataset records only 7 final IAC agreements since 1990 as compared to 63 final agreements for NIACs. Second, most scholars agree that international no longer recognizes “war” as a distinct legal category, rendering the signaling function largely unnecessary. The end of armed conflicts (the term largely replacing “war”) is now a factual question rather than a matter of formal termination. Third, the UN Security Council has in several cases partially or wholly taken over the settlement of conflicts, passing resolutions whose terms might, in a prior era, have appeared in a peace treaty. The most prominent is Resolution 687 (1991) for Iraq-Kuwait but there are many others.
Law bearing on IAC peace agreements now comes instead from cognate fields – the law of treaties, human rights, the jus ad bellum, the jus in bello, and the law of state responsibility (among others). Agreements ending NIACs (which have become much more common) are not generally recognized as binding treaties (because they necessarily include at least one non-state party) and as a result have a more indirect relationship to international law.
The Role of Coercion
Kehl properly focuses on a Russia-Ukraine agreement potentially being void under Article 52 of the VCLT because it would be “procured by the threat or use of force in violation of the principles of international law embodied in the Charter of the United Nations.” The critical underpinning for this means of voiding an agreement is, of course, the prohibition on the aggressive force itself in Article 2(4). Peace agreements procured by unlawful force are the “fruit of the poisonous tree” and cannot grant legal entitlements to aggressor states: ex injuria jus non oritor. The pivotal factor is that the force involved is unlawful: an aggressor state may not coerce agreement to a treaty while a state using force lawfully – in self-defense or as authorized by the Security Council – may do so.
The rule is uncompromising. Even if Ukraine were to find benefits in other parts of a peace treaty – security guarantees, no Russian opposition to seeking EU membership, compensation for wartime destruction, etc. — these cannot be weighed against the fact of coercion. VCLT article 44(5) provides that in cases of coercion, “no separation of the provisions of the treaty is permitted.” The entire treaty fails. (Since Ukraine and Russia are parties to the VCLT, there is no argument to be made that this and other procedural aspects of treaty law may not amount to custom).
On the other hand, those same procedures state that even a treaty coerced by force does not become void of its own accord. The Vienna Convention provides in Article 65(1) that only the coerced party can raise an objection of coercion (an objecting party must raise “a defect in its consent to be bound”). It must do so by sending a notice to other parties so that a process of evaluating the claim may take place. Such a burden on Ukraine to assert coercion as an affirmative defense (to use an American term) raises the prospect that it may simply choose not to do so (Dörr & Schmalenbach, p. 955). Indeed, one could make a good case that is what is likely to happen: why would Ukraine even enter into peace negotiations and do the hard work of reaching an agreement if it intended to declare the treaty void after its conclusion?
There is an alternative scenario. Ukraine might initially sign and ratify a peace treaty in order to buy time to revive and regroup its forces and rebuild infrastructure. If, later on, Russian control over the annexed territories appears tenuous and its resources for resupply limited, Ukraine might see a strategic opportunity to raise the coercion claim and void the treaty. Or there might be new leadership in Russia that reevaluates the strategic value of the territories, in which case it might not react with force if Ukraine denounced the treaty as void. Ukraine would not forfeit its coercion claim if it were to take such a wait and see approach (Dörr & Schmalenbach, p. 955).
If Ukraine made a coercion claim at any point and removed itself from the agreement, other states could continue as parties despite Ukraine’s departure. In accordance with VCLT article 69(4), voiding the consent of one party to a multilateral treaty means “that the treaty will nonetheless remain valid for the other parties.” (Aust, p. 280). As perverse as it might sound, one could imagine Russia and a Trump-led United States insisting that an agreement continue (i.e. Russian sovereign control over annexed territory continue) even if Ukraine denounced it as coerced. Article 69(4) could allow them to do so.
Notwithstanding the VCLT, viewing the treaty as void only upon Ukraine’s initiative seems at odds with fundamental principles. That the agreement should be void ab initio derives from Russia’s territorial gains themselves being void. As the Security Council declared of Iraq’s purported annexation of Kuwait in 1990, the act “has no legal validity, and is considered null and void.” (SC Res. 662 (1990)). How can a peace agreement ratifying such an illegal act and coerced through that illegal act nonetheless have legal validity? The entire reason for voiding a coerced treaty is the recognition that any consent is never truly voluntary, and making the viability of a coercion claim contingent on Ukraine’s failure to raise it would seem to replicate the false consent that the doctrine was designed to avoid.
Jus Cogens Invalidity
Russia’s use of force to annex Ukrainian territory may provide a second basis for invalidating the agreement: that it violates a peremptory norm under Article 53 of the VCLT. The prohibition on the aggressive use of force is the quintessential jus cogens norm, and the ILC has twice identified it as having a peremptory character – in commentary to its version of Article 53 (then Article 50) and in its 2022 Draft Conclusions on Peremptory Norms (Annex A). The claim would be that treaty provisions ratifying Russia’s annexation would also ratify the unlawful force giving rise to the annexation. A treaty in conflict with a jus cogens norm is void ab initio.
One objection to this claim is that, by its terms, a peace agreement would not require or even contemplate the illegal use of force. At most, the argument would go, the agreement would memorialize as a fait accompli the results of prior unlawful force. In a recent article, Ingrid Brunck and Monica Hakimi argue that the prohibition on annexation is historically and analytically distinct from Article 2(4)’s prohibitions and that the two ought not to be conflated. Indeed, the two ILC listings of peremptory norms mentioned above, while not exhaustive, both include aggressive force but do not include annexation. Anthony Aust states in his widely-cited book on treaty law that “perhaps the only generally accepted example [of a peremptory norm] is the prohibition on the use of force as laid down in the UN Charter” (p. 257).
Read full article
https://www.ejiltalk.org/a-legal-framework-for-a-russia-ukraine-peace-agreement/
