In This Article Expand or collapse the "in this article" section Countermeasures

  • Introduction
  • Introductory Works
  • Textbooks
  • Proportionality
  • Dispute Settlement
  • “Third” States
  • Treaty Law
  • Countermeasures and Cyberspace

International Law Countermeasures
Joaquín Alcaide Fernández
  • LAST REVIEWED: 22 April 2020
  • LAST MODIFIED: 22 April 2020
  • DOI: 10.1093/obo/9780199796953-0072


As used in modern practice, judicial decisions, and literature, the term “countermeasures” covers the main part of the classical subject of “reprisals,” to which the first monographs of international law were devoted in the 14th century (B. de Sassoferrato and G. de Legnano). Two features used to be attached to countermeasures: (a) they are unilateral or individual measures adopted directly and independently by a state that takes the law into its own hands as based on the state’s “subjective” qualification of another state’s prior act as illegal (“self-help” or “self-protection”); (b) the measures would be essentially illegal if not for the fundamental prerequisite of the “objective” existence of a prior wrongful act committed by the state against which the countermeasures are adopted, and for the fulfillment of other requirements, substantive limits, and procedural conditions. In legal literature sometimes countermeasures not only include these measures but also those called “retorsion”: these are unfriendly and perhaps also retaliatory but not illegal irrespective of the conduct of the state these measures are taken against. The measures of retorsion have fallen outside the scope of the International Law Commission’s (ILC’s) work on international responsibility. On the other hand, countermeasures are not always differentiated from “sanctions” (or institutionalized coercive measures), and from unilateral measures to enforce “sanctions.” The development of judicial and institutional processes for furthering compliance and enforcement in general international law has not yet excluded such unsatisfactory legal remedies, as states’ practice and opinio juris (or the judicial decisions) prove. Legal scholars are also practically unanimous to recognize the admissibility of law enforcement through countermeasures, whether they consider it expressly or implicitly an exception or a right/faculty (or duty) of states. And so, this recognition is extended to international organizations. The ILC has taken note of all that, having contributed to the more precise development and definition of the countermeasures’ legal regime. The debates have been mainly on the conditions and restrictions to neutralize or reduce the risk of abuse, less on the pros and cons of the codification of that regime. Concerning the legality and legitimacy of countermeasures, there are other requirements related to, inter alia, their object (law-enforcement, not punishment), necessity and proportionality, temporary and reversible character, or the other obligations where fulfillment cannot be suspended as a countermeasure, all of them addressed by the ILC’s draft articles on responsibility. Alongside the recurrent renewal of the discussion relating to the illegality of reprisals/countermeasures involving the use of force, there are probably two other controversial issues, as highlighted during ILC’s work: the interrelationship between recourse to means of dispute settlement and to countermeasures and, in relation to erga omnes obligations and peremptory norms, the entitlement (right or duty) of noninjured states to adopt individual countermeasures. Although the term “countermeasure” has been used since at least 1923, as a general concept, referring to domains or disciplines with little or no relation to international law (medicine, materials or electromagnetic engineering, pollution prevention, defense and weapons), in recent years some practice and several academic writings attempt to adapt existing international law, including the law governing the self-help resources available to the victim states (self-defense, retaliation, regression, and the right to take countermeasures), from the kinetic (physical) space to a new one (“the fifth domain”), namely, the cyber domain.

Introductory Works

While some authors remain skeptical about the relevance of enforcement mechanisms (“sanctions”), countermeasures must be put into a comprehensive perspective (social, political, historical, and legal) as a key piece of the foundations and legal basis of obligation of international law and the characterization of international law as a legal system (Fukatsu 1986, O’Connell 2008, Paddeu 2015), even if some authors consider that there cannot be a true system of sanctions based on interstate countermeasures (Leben 1982). Social, political, and historical context helps to explain the degree of development achieved in international law and international society relating the noncompliance of legal rules, as different from moral, social, and other kinds of rules. It is common to remark that the mechanisms conceived for furthering compliance and enforcement of international law are those that mainly justify to considering international law as a legal order more imperfect or primitive, or less developed, than the domestic laws. In the same way, the international society compared to national societies. Being a manifestation of private justice, like reprisals (Ruffert 2012), countermeasures bear the risk of being more destructive for the international legal order than the alleged prior international wrongful act itself. Moreover, one should realize the increasing significance of alternatives to state-centered enforcement (Damrosch 1997). So institutional mechanisms (through political but also arbitral or judicial processes) are increasingly an alternative to these unilateral or individual countermeasures. Sometimes institutional mechanisms impose the adoption of coercive measures or authorize those measures. Ultimately, arbitral tribunal awards or judicial decisions might have to be enforced by coercive measures. But institutional mechanisms may fail, and decentralized reactions will be justified (Sicilianos 1990). On the other hand, countermeasures must be defined vis-à-vis reprisals, retorsion, reciprocity, and sanctions (Alland 2010). Indeed, the International Law Commission (ILC) has concluded that (institutionalized) sanctions, which an international organization may be entitled to adopt against its members (states or other international organizations) according to its rules, are per se lawful measures and cannot be assimilated to countermeasures. Hence, there are theoretical and practical issues concerning the distinction between (institutionalized) sanctions and (unilateral) countermeasures, namely because the problem of legitimacy and legality assessment (Gowland-Debbas, et al. 2001; Picchio Forlati and Sicilianos 2004). States or international organizations might adopt countermeasures to react against a “wrongful” sanction adopted by an international organization (Tzanakopoulos 2011). Having been examined in relation to the international responsibility of states and international organizations, the study of the role of countermeasures has yet to treat in-depth the process of international responsibility allocated among multiple states, international organizations, and other actors (SHARES).

  • Alland, Denis. “The Definition of Countermeasures.” In The Law of International Responsibility. Edited by James Crawford, Alain Pellet, and Simon Olleson, 1127–1136. Oxford: Oxford University Press, 2010.

    Alland undertakes an attempt to determine the contours of the possible meanings vis-à-vis reprisals, retorsion, reciprocity, and sanctions and to evaluate which definition better reflects practice, since the ILC Articles of 2001 do not contain any definition. The author comments on the unilateral character of countermeasures, its pacific character, intrinsic unlawfulness and state control, and the differentiation from the challenge of treaties.

  • Damrosch, Lori Fisler. “Enforcing International Law through Non-forcible Measures.” Recueil des Cours: Collected Courses of The Hague Academy of International Law 269 (1997): 9–250.

    Poses conceptual questions concerning compliance and enforcement. The author deals with unilateral economic “sanctions” and measures in multilateral context, inside and outside formal institutional frameworks (illustrated basically through US practice), civil actions in national courts, and criminal actions in national and international tribunals.

  • Fukatsu, Ei’ichi. “Coercion and the Theory of Sanctions in International Law.” In The Structure and Process of International Law: Essays in Legal Philosophy, Doctrine, and Theory. Edited by Ronald St. J. Macdonald and Douglas M. Johnston, 1187–1205. Dordrecht, The Netherlands: Martinus Nijhoff, 1986.

    Fukatsu goes over the common elements to “sanctions” in general (moral, social, ethical, and legal) and considers international law as enforced by the reaction and interaction of states, that is, expectations, feelings of the essential importance of the pattern of conduct and coercion (diplomatic, economic, and military) exercised by individual states, a group of states, or international organizations.

  • Gowland-Debbas, Vera, Mariano García Rubio, and Hassiba Hadj-Sahraouira, eds. United Nations Sanctions and International Law. The Hague: Kluwer Law International, 2001.

    A collection of essays to reevaluate “sanctions” and the broader peace maintenance function of the Security Council in the light of current community concerns (human rights and humanitarian law, legal rights of implementing states and private rights). Part 1 is devoted to theoretical issues and addresses disputes concerning the definition of sanctions, including the analysis of “unilateral” countermeasures.

  • Leben, Charles. “Les contre-mesures inter-étatiques et les réactions à l’illicite dans la société international.” Annuaire Française du Droit International 28 (1982): 9–77.

    DOI: 10.3406/afdi.1982.2483

    Uses the term “countermeasures” to include both reprisals and retorsion and considers the countermeasures to be sanctions. He poses a question: can there be a true system of sanctions based on the resort to nonarmed countermeasures in interstate decentralized society? His answer is “no,” because of the unilateral character, the self-judging, etc.

  • O’Connell, Mary Ellen. The Power and Purpose of International Law: Insights from the Theory and Practice of Enforcement. Oxford: Oxford University Press, 2008.

    DOI: 10.1093/acprof:oso/9780195368949.001.0001

    O’Connell advocates the “power” (i.e., the ultimate legal authority) of international law and its reality and relevance, focusing on the role and availability of “sanctions” (including countermeasures, as peaceful “sanctions,” unilateral or collective) in international law. She revisits the legal literature and the international practice and legal rules.

  • Paddeu, Federica I. “Countermeasures.” In Max Planck Encyclopedia of Public International Law. Edited by Rüdiger Wolfrum and Margrét Sólveigardóttir. New York: Oxford University Press, 2015.

    Not included neither in the Bernhardt’s Encyclopedia (1981–1990) nor in the print edition of the Wolfrum’s Max Planck Encyclopedia (2012, 2013), this entry synthesizes the history and development of countermeasures and restates its current regulation, dealing with specific issues.

  • Picchio Forlati, Laura, and Linos-Alexander Sicilianos, eds. Economic Sanctions in International Law. Leiden, The Netherlands: Martinus Nijhoff, 2004.

    Presents the current state of research and a selection of the research of some of the participants in the 2000 session of the Center for Studies and Research of the Academy of International Law of The Hague. “Sanctions” include institutional sanctions and decentralized countermeasures, as well as the often inextricable intertwining between these two levels.

  • Ruffert, Matthias. “Reprisals.” In Max Planck Encyclopedia of Public International Law. Vol. 8. 2d ed. Edited by Rüdiger Wolfrum, 927. Oxford: Oxford University Press, 2012.

    The author completely rewrites K. J. Partsch, “Reprisals,” in Encyclopedia of Public International Law, Vol. 9, International Relations and Legal Cooperation in General Diplomacy and Consular Relations, edited by Rudolf Bernhardt (Amsterdam: North-Holland, 1986), pp. 330–335, dealing with historical evolution and current concept, definition, and legal situation of reprisals as countermeasures in times of war. Available online by subscription, last updated September 2015.


    Research Project of the Amsterdam Center for International Law, led by André Nollkaemper, and funded by the European Research Council. SHARES examines the nature and extent of the problem of sharing responsibility allocated among multiple states and other actors in an increasingly interdependent and heterogeneous legal order. The project offers new concepts, principles, and perspectives for understanding how the international legal order deals with shared responsibility.

  • Sicilianos, Linos-Alexander. Les réactions décentralisées à l’illicite: Des contre-mesures à la légitime défense. Paris: Librairie Générale de Droit et Jurisprudence, 1990.

    Attempting to theorize on the failure of UN law, the author analyzes the principle (circumstances that back the right of states to react) and the substance (conditions to be observed for the reaction being in accordance with international law) of the decentralized (re)actions to prior wrongful acts.

  • Tzanakopoulos, Antonios. Disobeying the Security Council: Countermeasures against Wrongful Sanctions. New York: Oxford University Press, 2011.

    DOI: 10.1093/acprof:oso/9780199600762.001.0001

    Examines how the UN Security Council, in exercising its power to impose sanctions under Article 41 of the UN Charter, may violate the charter itself and general international law. The author posits that the international responsibility of the UN may be implemented through countermeasures.

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