Introduction

The European Union’s (EU) response to Russia’s invasion of Ukraine has been marked by an unprecedented expansion of unilateral sanctions. These ‘restrictive measures’, aimed at curbing Russia’s ability to wage war, have rapidly increased in scope, reach, and intensity, targeting almost every facet of the Russian economy. While sanctions have long been part of the EU’s Common Foreign and Security Policy (CFSP), the sheer scale of the measures now in place raises pressing legal questions—most notably about their proportionality.

The principle of proportionality, common to many areas of law, serves as a check on excessive or unjustified government action. However, assessing the proportionality of EU sanctions is not a straightforward exercise. These measures exist within a layered legal order: at the EU level, they must comply with requirements under the EU Treaties, most particularly fundamental rights and the principle of proportionality; at the international level, they may be justified as countermeasures under the law of state responsibility; and at the trade level, they must adhere to World Trade Organization (WTO) rules, notably the security exceptions.

Understanding the legal boundaries of EU sanctions requires considering how these overlapping legal regimes operate, each imposing distinct constraints on the EU’s ability to impose unilateral measures.

The Evolving Landscape of EU Sanctions

Since February 2022, the EU has adopted fifteen successive sanctions packages against Russia. The unprecedented scope of this sanctions regime—in terms of targeted individuals, sectors and extraterritorial reach—is intended to maximise pressure on Russia and compel it to cease its military aggression.

Several trends highlight the growing complexity of EU sanctions. First, the EU has significantly broadened the criteria for individual listings, moving beyond those directly involved in military operations to include individuals ‘benefitting from’ the Russian government, ‘leading businesspersons operating in Russia’, and those associated with them. Second, sectoral sanctions have become increasingly comprehensive, covering critical industries such as energy, technology, and finance, while broadcasting bans have been imposed on Russian media outlets. Third, the EU has introduced anti-circumvention measures with extraterritorial reach, penalising entities in third countries suspected of helping Russia evade sanctions. Finally, the adoption of sanctions has come paired with an increasingly punitive rhetoric, with President von der Leyen vowing to make Russia ‘pay’ for its actions in Ukraine.

As their scope widens, the unintended effects of these sanctions are felt globally. They have affected not only the Russian population, but also third countries through rising inflation, energy insecurity, and shortages in supply chains. Sanctions also have significant human rights implications, restricting freedom of speech and property rights, as well as exacerbating socio-economic inequalities due to deteriorating economic conditions.

Despite the intensification of EU sanctions, the EU maintains that restrictive measures are ‘designed to be proportionate to the objectives they seek to achieve’. However, as the following sections will show, proportionality is applied differently depending on the legal framework in question, and each framework is marked by its own judicial and legal constraints.

Proportionality in EU Law: A Limited Judicial Constraint

Proportionality is a fundamental principle of EU law, ensuring that ‘the individual should not have his freedom of action limited beyond the degree necessary in the public interest’. In the context of restrictive measures, proportionality serves a dual role: it functions as a principle of good governance (Article 5(4) Treaty of the European Union (TEU)) and as a safeguard for fundamental rights (Article 52(1) of the Charter of Fundamental Rights).

The content of the proportionality principle has been entirely developed by the Courts. In theory, it consists of a three-step test to determine whether (i) the measure is appropriate to achieve a legitimate objective (suitability), (ii) no less restrictive alternatives are available (necessity), and (iii) the measure does not excessively impact the interests of the concerned individuals (proportionality in the narrow sense).

However, the role of proportionality in EU sanctions law is constrained by two key factors. First, the Court of Justice of the European Union (CJEU) has only limited jurisdiction over CFSP measures. Article 275 of the Treaty on the Functioning of the European Union (TFEU) precludes the Court from reviewing the legality of CFSP acts, except for ‘restrictive measures against natural or legal persons’. In the past, the Court interpreted this exception narrowly, excluding measures of general scope—such as trade and financial restrictions—from its review (Rosneft).. However, the CJEU has sought to address this gap by relying on the principle of effective judicial protection to expand its jurisdiction beyond the strict boundaries set by the Treaties (Venezuela). Despite this gradual shift toward broader judicial oversight, the precise limits of the Court’s jurisdiction over general CFSP measures remain uncertain.

Second, even when the Court exercises jurisdiction, it applies a highly deferential proportionality test. Given the inherently political nature of the CFSP, the Court generally restricts its review to assessing whether the restrictive measure is ‘manifestly inappropriate’ for achieving its objective (Rotenberg)—a relatively low threshold that grants the EU Council considerable discretion in designing sanctions. The broad and flexible objectives of the Russian sanctions regime make it easy to satisfy this lenient suitability test. As a result, asset freezes, for example, are rarely struck down by the Court on this ground, as it consistently finds that such measures are reasonably connected to the overarching goal of weakening the Russian economy.

The Court appears to apply different levels of scrutiny depending on whether a case involves socio-economic rights or civil and political rights. In RT France, the General Court conducted a more rigorous review when assessing a broadcasting ban on a Russian state-owned media outlet. In evaluating the alleged violation of freedom of expression, the Court not only examined the suitability of the measure but also considered its necessity and impact on the applicant. Nevertheless, the Court upheld the ban as proportionate in view of the Council’s broad discretion in political matters—a judgment that has since faced criticism.

These cases illustrate that, in practice, the proportionality principle does not function as a strong legal constraint on EU sanctions. Nevertheless, in accordance with the objectives of the EU’s external action (Article 21 TEU), restrictive measures must also align with international law obligations. Therefore, they must also be assessed under the applicable rules of countermeasures and WTO law.

Proportionality in Countermeasures: The Law of State Responsibility

Countermeasures are unilateral responses to internationally wrongful acts, permitted under the International Law Commission’s (ILC) Articles on State Responsibility (ARSIWA). These measures involve the temporary non-performance of an international obligation with the objective of inducing the responsible state to comply with its legal duties. Importantly, countermeasures are not intended as punishment for wrongful conduct.

Many of the EU’s restrictive measures—such as sanctions against Russia’s key financial institutions—qualify as countermeasures in response to Russia’s violation of the prohibition on the use of force under Article 2(4) of the UN Charter.

Article 51 ARSIWA stipulates that countermeasures ‘must be commensurate with the injury suffered, taking into account the gravity of the internationally wrongful act and the rights in question.’ The ILC Commentaries clarify that proportionality is distinct from the necessity of the measure. Instead, it requires a balance between the countermeasure and the internationally wrongful act. This assessment involves both a quantitative evaluation—comparing the intensity of the injury with the impact of the countermeasure—and a qualitative consideration of the seriousness of the breach and the significance of the rights involved.

This balancing approach differs from the means-end rationality of the proportionality principle in EU law. Some scholars have even likened Article 51 ARSIWA to the biblical ‘eye for an eye’ principle. However, in cases of erga omnes violations—such as Russia’s military aggression against Ukraine—a strict tit-for-tat interpretation could risk justifying excessively far-reaching countermeasures.

Moreover, such an interpretation is inconsistent with the coercive function of countermeasures, which excludes punitive measures. Instead, the arbitral tribunal in ADM v. Mexico offers an alternative reading of Article 51 ARSIWA, assessing proportionality in light of the coercive purpose of countermeasures, which must be ‘necessary and reasonably connected with the aim purportedly pursued.’

Ultimately, the ARSIWA leaves considerable room for interpreting the legal limits of countermeasures. However, most sanctioning entities—including the EU—avoid invoking countermeasures as a legal basis for sanctions, likely to sidestep the constraints imposed by this framework. In any case, many sanctions fall outside the scope of countermeasures altogether. For instance, anti-circumvention measures targeting third states cannot be justified as countermeasures, as they do not respond to a prior wrongful act. Additionally, the increasingly punitive rhetoric surrounding the EU’s restrictive measures against Russia may be difficult to reconcile with the requirement that countermeasures serve a coercive, rather than punitive, purpose. For those measures, the legal boundaries remain vague, and we must fall back on the proportionality requirements of EU law and, where applicable, the security exceptions in WTO law.

WTO Law and the National Security Exception

Many of the EU’s sanctions involve trade restrictions, making WTO law another relevant legal framework. While WTO rules generally prohibit unilateral trade barriers, certain provisions such as Article XXI of the General Agreement on Tariffs and Trade (GATT) provide an exception for measures taken for national security reasons.

Article XXI allows Member States to take ‘any action which it considers necessary for the protection of its essential security interests’ in times of international crisis. In Russia – Traffic in Transit, the Panel clarified that this provision is not entirely self-judging but refrained from assessing the necessity of the measure, leaving it to the discretion of the Member State. However, this discretion is constrained by the principle of good faith, requiring states to establish a plausible link between the measure and their security interests. While this does not amount to a full proportionality test, it imposes a suitability-based limitation on trade-related sanctions.

Conclusion

The unprecedented expansion of EU sanctions against Russia highlights the complex and often uncertain legal limits of restrictive measures. While the EU maintains that its sanctions are proportionate to their objectives, the application of proportionality varies significantly across legal frameworks, each imposing distinct limitations.

In EU law, proportionality is a fundamental principle, but it imposes only a weak constraint on restrictive measures. The CJEU’s limited jurisdiction over CFSP measures and its deferential review grant the Council broad discretion in designing sanctions, with proportionality assessments largely confined to ensuring that a measure is not ‘manifestly inappropriate’. In contrast, proportionality in the ARSIWA follows a balancing approach, weighing the gravity of the wrongful act against the countermeasure’s impact. While this test is more structured than the EU’s, it remains open to broad interpretation. Meanwhile, WTO law does not apply a strict proportionality test but imposes a good-faith requirement under the security exception, functioning as a light suitability test.

Despite these safeguards, the increasingly punitive rhetoric surrounding EU sanctions blurs the line between coercive and punitive measures, raising concerns about their legal justification. Additionally, the extraterritorial reach of anti-circumvention measures further tests the boundaries of lawful sanctions. As the EU navigates this evolving legal landscape, ensuring coherence across legal frameworks is crucial—not only to uphold the legitimacy of its sanctions but also to mitigate unintended global consequences.

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Posted by Marie Terlinden, Doctoral Researcher at KU Leuven & Fellow at Research Foundation – Flanders (FWO)