Playing Chess with Missiles: Russia’s Game of Anticipatory Self-Defense?

By Pratama Tambunan

Pratama is currently an exchange student at the University of Pennsylvania. Before coming to Penn, he was a senior at the Faculty of Law at Universitas Gadjah Mada, Indonesia.

​There has long been an understanding in international relations that an attack against another state (or legally termed as ‘use of force’), is to some extent plausible in international law—provided that it is masked under the traditional doctrine of self-defense. Article 2(4) of the United Nations Charter (“UN Charter”) expressly states that “All Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the Purposes of the United Nations.” One then could imply that a textual interpretation of the UN Charter, based on the ordinary meaning of the term, suggests that force can be permitted if it is consistent with the Purposes of the UN. Just rightly so, as clarified in the 2003 Oil Platforms Case, which addressed the lawfulness of the United State’s attack against certain oil platforms in Iran after the 2003 Iranian attacks against the United State’s consulate, the International Court of Justice (“the Court”) clarified that the one justification for a State’s use of force is self defense. The court pointed towards the existing right of self-defense ingrained under Article 51 of the UN Charter which states, “Nothing in the present Charter shall impair the inherent right of individual or collective self-defense if an armed attack occurs against a Member of the United Nations, until the Security Council has taken measures necessary to maintain international peace and security.” This is not a contested issue in international law.

Leap forward to the beginning of 2022; Russian military forces have initiated their advance toward Donbas coupled with missile strikes and kamikaze drone attacks targeting Kyiv. This left no room for doubt that Russia was unambiguously employing military force within the territory of another sovereign state, under the meaning of Article 2(4) of the UN Charter. In this case, there was no place for political euphemisms or diplomatic jargon to conceal President Putin's actions. Yet, while the international community swiftly and sternly criticized President Putin's war declaration, as responsible global observers, it's essential to consider the situation from all angles.
Within President Putin's official declaration of war, available for public perusal on the Kremlin's website, I discovered a set of intriguing observations pertaining to his decision to go to war. His remarks included a critique of what he perceived as Western states' hypocrisy, especially regarding their military interventions in the Middle East, and he also raised the notion of exercising the right of collective self-defense on behalf of the Luhansk and Donetsk People's Republics, a topic deserving of deeper exploration at a later time. Additionally, he shed light on the historical economic factors influencing the relationship between Russia and Ukraine.

However, what added an extra layer of intrigue to his speech was the manner in which he repeatedly emphasized the potential risks of a sudden attack on Russia due to Ukraine's close affiliations with NATO. From the perspective of many international legal experts, these statements seemed to imply an invocation of preemptive self-defense, a theoretical and expansive interpretation of Article 51 of the UN Charter. This interpretation suggests that self-defense could be employed based on the belief or knowledge of an impending armed attack. Yet, it's crucial to note that such a concept has struggled to gain acceptance within the realm of international law. The requirement for preemptive self-defense has often been viewed as a loophole that could permit states to utilize significant military force based on speculative information, making it a challenging and contentious concept in the arena of global diplomacy.

As the idea of preemptive self-defense faces growing skepticism in international circles, a related concept, known as anticipatory self-defense, is gradually gaining support in the realm of international law. In this concept, states have the right to take self-defense measures when faced with an "imminent" armed attack, an attack that is essentially pending and unavoidable (in simple, yet much of the debate is delineating when something is imminent). Thanks to the blessings of the internet, taking rapid action based on high-quality intelligence and information is not just a possibility but often the key to preventing the loss of countless lives.

Consider a scenario where Russian intelligence accurately predicted an impending attack by Ukraine on Russian territory. In this situation, it would seem morally justifiable for Russia to act swiftly to protect the lives of its citizens. However, the pressing issue here is the question of the legal basis for such action.

In the realm of international law, which predominantly consists of treaties and international customary practices, our initial inclination is to explore this domain. However, it's important to note that there's currently a conspicuous absence of any international treaties specifically addressing the concept of anticipatory self-defense. While there are indeed provisions within Jus ad Bellum in International Humanitarian Law (IHL), the closest international law has come to acknowledging this concept is rooted in Article 51 of the United Nations (UN) Charter.

Nevertheless, it's worth emphasizing that the rules governing treaty interpretation are well-established in the field of international law. Article 31 of the Vienna Convention on the Law of Treaties (VCLT) provides guidance on how to interpret a particular treaty. It underscores the importance of interpreting a treaty in good faith, in accordance with its terms, and with due consideration to its context and overarching purpose. Regrettably, when examining these interpretive sources, such as the drafting history, there is a notable absence of any indications that the drafters envisioned anticipatory self-defense falling under the purview of the same article.

To shed further light on this matter, we can turn to relevant case law, such as the 1986 Nicaragua case, which revolved around United States aggression in Nicaraguan territory. In this landmark case, the Court did indeed offer an interpretation of Article 51 of the UN Charter. Notably, the Court primarily clarified the conditions that must be met for a valid claim of self-defense, emphasizing the necessity of suffering an armed attack, the requirement for a defensive response, and the need for the chosen method to be proportionate to the harm endured. However, it did not make any explicit references to the requirement for an impending armed attack, leaving this issue unaddressed.
However, there is reason to be hopeful that customary international law could offer a solution to this legal void. Customary international law represents one of the most challenging sources of law to unravel because it is often not codified in written texts or treaties. Instead, it is established through the consistent practice of states and opinio juris, which is the belief that there is a legal obligation. This evolving landscape suggests that anticipatory self-defense could find its place within customary international law.

Few practices come to mind, looking back to the 1946 Tokyo Trials, the court explicitly acknowledged the legitimacy of the Dutch declaration of war in response to an "imminent armed attack" by Japan, all without the need for reference to a specific treaty. Moreover, both the Security Council and the General Assembly declined to condemn Israel for its preemptive attack in 1967 against specific belligerent Arab states. In doing so, they effectively conveyed the United Nations' implicit endorsement of Israel's use of anticipatory self-defense in 1967. This historical precedent indicates a growing recognition of the concept of anticipatory self-defense. Moreover, within the international community, there is a growing chorus of support for this principle, championed by prominent international scholars, state representatives, and even judges of the International Court of Justice (ICJ).

One such example is Judge Robert Ago, who served on the International Court of Justice from 1979 to 1995. In his professional capacity, Judge Ago noted in an Addendum to the International Law Commission's 8th Report on State Responsibility that international law may indeed be receptive to the idea of self-defense in the face of an "imminent armed attack." Moreover, the United Kingdom, through Attorney General Jeremy Wright QC MP, openly voiced its active support for the right of self-defense when confronted with an imminent threat back in 2017. These instances underscore the emergence of opinio juris, a sense of legal obligation, among certain states, indicating a shifting tide in favor of recognizing anticipatory self-defense as a valid principle in customary international law.

Setting aside the question of whether international customary law incorporates anticipatory self-defense, there remains substantial debate on whether self-defense is a valid claim for Russia. As Yves Derain once noted, the key prerequisite for a right of self-defense is the existence of an armed attack, which serves as the trigger. Without an armed attack (or, in the context of anticipatory self-defense, an imminent armed attack), any claim to self-defense lacks coherence. However, establishing the existence of an armed attack is not as straightforward as Putin suggests. To provide a clearer perspective, even the mobilization of troops into another nation's territory may not necessarily constitute an armed attack, necessitating a more in-depth analysis.

In the Nicaragua case, an armed attack, as per Article 51, requires certain criteria: it must be relatively large in scale, possess sufficient gravity, and result in a substantial effect. The International Court of Justice (ICJ) has emphasized that "mere frontier incidents" do not meet the necessary gravity to be classified as armed attacks. Nevertheless, the ICJ does not establish concrete boundaries for what can be considered an armed attack; instead, it varies based on the specific circumstances of each case. In the context of anticipatory self-defense, the difficulty is compounded. Not only must the party claiming self-defense demonstrate the imminence of an attack (imminence meaning at the last opportunity), but also that this attack carries significant gravity to qualify as an armed attack. Given the information Russia has shared, it is challenging to assert the likelihood of an armed attack. In other words, the threat must be palpably imminent. The "indications and warnings" of imminent attack, in this sense, correspond to the types of activities Russian forces were conducting in Russia, Belarus, and the Black Sea. In contrast, the United States and NATO were not engaged in activities that suggested they were preparing to attack Russia on short notice. Even NATO's defensive actions cannot be categorized as such; the limited deployment of forces in the region and near the Russian border did not provide NATO with a meaningful offensive capability against Russian forces. It is even questionable whether they provided any defensive capability beyond ensuring that NATO would respond if Russians crossed the border. There is no indication that NATO had decided to attack Russia.

This holds true even if Crimea is considered part of Russia, which, as a matter of law, it is not (refer to Geiss). There is no evidence to suggest that NATO or Ukraine had plans to retake Crimea through an attack. Furthermore, even if such intentions existed, the necessary forces were not in place to execute the operation effectively, eliminating any last window of opportunity. On the contrary, Russia and Western nations were engaged in a series of negotiations over the situation, during which Russia held a military advantage. Consequently, Russia's actions are, at best, an example of "preventive self-defense" and, at worst, and most accurately, pure aggression.
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In this intricate legal context, one fundamental truth emerges: the matter is far from being definitively resolved. The concept of anticipatory self-defense, although gaining recognition, lacks a universally accepted status within the realm of international law. What adds to the complexity is the absence of a single authoritative body that can unequivocally proclaim a practice as international custom, or one with the ability to fairly describe when an attack is considered imminent due to varying perspectives. Consequently, determining whether Russia's reliance on anticipatory self-defense can be legally justified remains an intricate challenge. It is worth noting that international customary law does not mandate a rule to be formally acknowledged in a specific forum to be considered binding. Therefore, the issue of whether anticipatory self-defense is a legitimate basis for Russia's actions cannot be conclusively settled until it is examined, possibly in a court of law or through discussions in international forums such as the United Nations Security Council.