Compulsive Means of Settlement of International Dispute: Retortion, Reprisals, Embargo, Pacific Blockade, and Intervention

Key Takeaways

• Compulsive means of settlement of international disputes are measures adopted by States to exert pressure on another State to resolve a dispute, fulfil an international obligation or discontinue wrongful conduct. They differ from ordinary peaceful methods because they involve coercion or pressure.
• Retortion refers to an unfriendly but lawful act taken by one State against another. Examples include withdrawing voluntary foreign aid, restricting diplomatic contacts and imposing otherwise lawful trade restrictions.
• Reprisals traditionally involved retaliatory acts that would ordinarily violate international law. Modern international law recognises certain non-forcible countermeasures under strict conditions, while armed reprisals are prohibited as a method of peacetime dispute settlement.
• Embargo means restricting or prohibiting trade, supplies or specified economic transactions with another State. Embargoes may be imposed independently or pursuant to sanctions authorised by the United Nations Security Council.
• Pacific blockade historically involved the use of naval forces to block access to another State’s ports or coastline without declaring war. Its traditional use is generally incompatible with modern restrictions on the threat or use of force.
• Intervention involves interference by one State in matters falling within another State’s sovereign authority. Coercive intervention is generally prohibited, particularly where military force or support for armed groups is involved.
• The United Nations Charter regulates the legality of coercive measures. Articles 2(3) and 2(4) require peaceful settlement of disputes and prohibit unlawful threats or uses of force. Articles 41 and 42 empower the Security Council to adopt non-military and military enforcement measures respectively.

What Are Compulsive Means of Settlement of International Disputes?

Compulsive means of settlement of international disputes are methods through which a State attempts to compel another State to resolve a disagreement, respect its international obligations or modify its conduct by applying diplomatic, economic, political or military pressure.

International disputes may arise over territorial boundaries, diplomatic relations, treaty obligations, trade restrictions, maritime rights, environmental matters or violations of international law. States generally attempt to settle these disputes through peaceful procedures such as negotiation, mediation, conciliation, arbitration and judicial settlement.

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However, peaceful negotiations may sometimes fail to produce an agreement. Traditionally, international law recognised several methods through which States could exert pressure on one another to secure compliance with their demands.

These methods became known as compulsive or coercive means of settlement.

The five traditional compulsive means are:

1. Retortion: Adopting lawful but unfriendly measures against another State.
2. Reprisals: Responding to an internationally wrongful act through retaliatory measures, subject to modern legal restrictions.
3. Embargo: Restricting trade, supplies or economic transactions with another State.
4. Pacific Blockade: Using naval forces to prevent maritime access to another State’s ports without formally declaring war.
5. Intervention: Interfering coercively in another State’s affairs to influence its decisions or conduct.

These methods differ in their nature, intensity and legal consequences. Some remain permissible under international law, while others have become unlawful or are permitted only in exceptional circumstances.

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Importantly, coercive measures do not necessarily result in the legal settlement of a dispute. They may encourage negotiation or compliance, but they can also aggravate international tensions.

Retortion

What Is Retortion in International Law?

Retortion is an unfriendly but lawful act taken by one State in response to the conduct of another State.

It is a form of political, diplomatic or economic pressure that does not violate the international legal obligations of the State taking the action.

Retortion is based on the principle that a sovereign State may adopt measures within its lawful authority, even when those measures are unfavourable to another State.

For example, suppose State A adopts an unfriendly diplomatic policy towards State B. State B may respond by reducing diplomatic engagement or discontinuing voluntary economic assistance. If these actions do not violate international obligations, they constitute retortion.

The purpose is generally to express dissatisfaction, protect national interests or encourage the other State to reconsider its conduct.

What Are the Essential Features of Retortion?

Retortion has the following characteristics:

• Lawful Nature: Retortion must remain within the limits of international law. Although the action may be politically unfriendly, it must not breach treaties or other binding international obligations.
• Unfriendly Conduct: The measure expresses dissatisfaction with another State’s policies or actions. It may affect diplomatic, commercial or political relations.
• Exercise of Sovereign Rights: A State generally adopts retortion by exercising powers that it already possesses under international law.
• Absence of a Required Prior Wrongful Act: Retortion can be adopted in response to conduct that is merely unfriendly. The conduct prompting retortion does not necessarily have to constitute an internationally wrongful act.
• Pressure Without Unlawful Force: Retortion ordinarily operates through lawful diplomatic or economic measures rather than military coercion.

What Are the Examples of Retortion?

Common examples include:

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• Withdrawal of Voluntary Foreign Aid: A State may discontinue financial or developmental assistance voluntarily provided to another State. Such withdrawal may constitute retortion if no binding agreement requires the assistance to continue.
• Restrictions on Diplomatic Relations: A State may recall its ambassador, reduce diplomatic engagement or restrict non-essential diplomatic cooperation to express dissatisfaction. However, such measures must respect applicable diplomatic obligations.
• Trade Restrictions: A State may impose tariffs or restrict particular commercial activities where such measures are permitted under applicable trade agreements and international law.
• Cancellation of Voluntary Cooperation: A State may suspend cultural exchanges, voluntary training programmes or other non-binding forms of international cooperation.

Is Retortion Legal Under International Law?

Retortion is generally lawful because it does not involve the breach of an international obligation.

The International Law Commission distinguishes retortion from countermeasures on this basis. Its commentary on the Articles on Responsibility of States for Internationally Wrongful Acts recognises that retortion may include restrictions on diplomatic relations, embargoes and withdrawal of voluntary aid.

However, the legality of any particular measure depends on the international obligations applicable to the State taking it.

Reprisals

What Are Reprisals in International Law?

Reprisals traditionally referred to acts of retaliation taken by one State against another State in response to an earlier internationally wrongful act.

Such measures would ordinarily violate international law but were historically claimed to be justified because of the wrongdoing committed by the other State.

The purpose of reprisals was to compel the responsible State to discontinue its unlawful conduct, provide reparation or comply with its legal obligations.

For example, if State A unlawfully violated an obligation owed to State B, State B might respond by temporarily withholding performance of certain obligations owed to State A.

The modern legal treatment of such conduct depends on whether it qualifies as a lawful countermeasure.

The term reprisals is now particularly associated with retaliatory measures during armed conflicts, while countermeasures is generally used for non-forcible responses to internationally wrongful acts outside armed conflict.

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What Are the Essential Features of Reprisals?

Traditionally, reprisals were characterised by the following elements:

• Previous Wrongful Conduct: Reprisals were undertaken in response to an alleged violation of international law by another State.
• Retaliatory Character: The measures involved responding to wrongful conduct through actions that would ordinarily be prohibited.
• Purpose of Securing Compliance: Their objective was to compel the responsible State to fulfil its international obligations rather than merely impose punishment.
• Relationship With the Original Wrong: The response was expected to bear a reasonable relationship to the earlier violation.
• Legal Limitations: Modern international law substantially restricts the measures that States may lawfully adopt in response to wrongful conduct.

What Are Countermeasures Under Modern International Law?

Countermeasures are non-forcible measures adopted by an injured State against a State responsible for an internationally wrongful act to induce compliance with its obligations.

The International Law Commission’s Articles on Responsibility of States for Internationally Wrongful Acts, adopted in 2001, provide an important framework for understanding countermeasures.

These Articles are not themselves a treaty, although several of their provisions reflect customary international law.

Article 22 recognises that the wrongfulness of an act may be precluded when it constitutes a countermeasure taken in accordance with the applicable rules of State responsibility under international law.

Articles 49 to 53 explain the principal requirements.

1. Purpose of Countermeasures: Article 49

Countermeasures must be directed against the State responsible for an internationally wrongful act. Their purpose must be to induce that State to fulfil its obligations, including cessation and reparation.

They must involve only temporary non-performance of obligations and should, as far as possible, permit the resumption of normal performance.

2. Prohibited Measures: Article 50

Countermeasures cannot affect certain fundamental international obligations, including:

• The prohibition against the threat or use of force.
• Obligations protecting fundamental human rights.
• Humanitarian obligations prohibiting reprisals.
• Obligations arising under peremptory norms of general international law.

3. Proportionality: Article 51

Countermeasures must be commensurate with the injury suffered, considering the gravity of the internationally wrongful act and the rights involved.

4. Procedural Requirements: Article 52

Ordinarily, the injured State must call upon the responsible State to fulfil its obligations, notify it of the proposed countermeasures and offer negotiations.

The Article also provides for urgent measures and circumstances requiring suspension of countermeasures.

5. Termination: Article 53

Countermeasures must end once the responsible State has complied with its obligations arising from the internationally wrongful act.

Are Armed Reprisals Permitted Under International Law?

Armed reprisals are prohibited as a means of peacetime dispute settlement under the contemporary prohibition against unlawful force.

Article 2(4) of the UN Charter prohibits the threat or use of force against the territorial integrity or political independence of States or in any other manner inconsistent with the purposes of the United Nations.

A State cannot justify an otherwise unlawful armed attack merely by describing it as retaliation for another State’s wrongful conduct.

The lawful exercise of self-defence under international law is a separate legal question and must satisfy its own requirements.

Reprisals during armed conflict are governed by international humanitarian law. For example, Article 33 of the Fourth Geneva Convention prohibits reprisals against protected persons and their property.

What Is the Difference Between Retortion and Reprisals?

The principal distinction concerns the legality of the act itself.

Retortion involves conduct that is already lawful, whereas traditional reprisals involved conduct that would ordinarily be unlawful and required a separate legal justification.

Modern countermeasures may preclude the wrongfulness of certain otherwise unlawful non-forcible acts when the applicable legal conditions are satisfied.

Thus, retortion is generally less legally complicated than countermeasures.

Embargo

What Is an Embargo in International Law?

An embargo is a restriction or prohibition imposed by a State or an international organisation on trade, supplies or certain economic transactions involving another State.

It is commonly used to exert economic or political pressure on a State to change its conduct, comply with international obligations or address a dispute.

For example, State A may prohibit the export of specified goods to State B in response to a dispute concerning treaty violations. Such a measure may be described as an embargo.

An embargo does not necessarily involve the use of military force. It generally operates through restrictions on the movement of goods, services or other commercial activities.

However, the word embargo is sometimes used broadly in political discussions. Its precise legal character depends on the nature of the restrictions and the legal authority under which they are imposed.

What Are the Different Types of Embargo?

Embargoes may be classified according to their scope and purpose.

• Trade Embargo: A trade embargo restricts the import or export of goods between States. It may cover selected products or a broad range of commercial transactions. Such restrictions can affect international trade, domestic industries and access to essential goods.
• Arms Embargo: An arms embargo prohibits or restricts the supply, sale or transfer of weapons, ammunition and related military equipment to specified States or other designated recipients. Arms embargoes are frequently used in international sanctions regimes to restrict the availability of military equipment during conflicts.
• Economic Embargo: An economic embargo may involve extensive restrictions on commercial and economic relations with another State. Depending on its scope, it may affect trade, financial transactions, investment and access to particular resources.
• Selective Embargo: A selective embargo targets particular goods, industries, entities or transactions rather than imposing comprehensive restrictions on all economic activities. For example, restrictions may be limited to military equipment or specified technology.

What Is the Legal Basis of an Embargo?

The legality of an embargo depends on the international obligations of the State imposing it and the legal basis for the restrictions.

Embargoes may operate as lawful acts of retortion where no international obligation is violated.

In certain circumstances, trade restrictions that would ordinarily breach international obligations may be assessed under the law governing countermeasures.

Embargoes may also be imposed through decisions of the United Nations Security Council.

Article 41 of the United Nations Charter authorises the Security Council to adopt measures that do not involve the use of armed force.

These measures may include the complete or partial interruption of economic relations and other forms of communication.

Consequently, the Security Council may impose economic sanctions, including trade and arms embargoes, where the requirements of Chapter VII are satisfied.

Is an Embargo Always Lawful?

An embargo is not automatically lawful merely because it does not involve military action.

Its legality may depend on several considerations:

• Whether the restrictions violate applicable trade agreements or other international obligations.
• Whether the measure has a valid justification under international law.
• Whether it complies with applicable rules on countermeasures, where that justification is invoked.
• Whether the restrictions conflict with binding Security Council decisions.
• Whether the measures comply with relevant international human rights and humanitarian obligations.

Embargoes should also be distinguished from maritime blockades. An embargo generally operates through legal and economic restrictions, whereas a blockade involves physically obstructing maritime access and may constitute a use of force.

Pacific Blockade

What Is a Pacific Blockade in International Law?

A pacific blockade is a historical method of international coercion in which one State uses naval forces to block access to the ports or coastline of another State without formally declaring war.

The term pacific was used because the blockade was imposed outside a formally declared state of war. It did not mean that the measure was peaceful in the ordinary sense.

The primary purpose of a pacific blockade was to compel another State to comply with demands, settle claims or fulfil particular obligations.

For example, a State might historically have positioned warships near another State’s ports to obstruct maritime commerce until certain demands were accepted.

Although pacific blockades were discussed as methods of settlement in traditional international law, their legality has been substantially affected by the development of the prohibition against force.

What Are the Essential Features of a Pacific Blockade?

A traditional pacific blockade had the following characteristics:

• Use of Naval Forces: Warships were deployed to restrict access to designated ports or coastal areas. The measure therefore involved military power, even where the States were not formally at war.
• Absence of a Formal Declaration of War: The blockading State generally attempted to apply pressure without formally declaring war against the targeted State.
• Restriction of Maritime Commerce: The blockade was intended to interfere with shipping and commercial activities involving the targeted State.
• Coercive Purpose: The objective was to compel the targeted State to satisfy demands, provide compensation or modify its conduct.
• Questions Concerning Third States: Historically, the treatment of ships belonging to third States created significant legal difficulties. Interference with neutral commerce raised questions concerning maritime rights and the interests of States not directly involved in the dispute.

What Are the Historical Examples of Pacific Blockade?

Two commonly discussed historical examples are:

• British Blockade of Greece, 1850: Britain imposed coercive naval measures against Greece in connection with claims involving British subjects, including the Don Pacifico dispute. The episode illustrates the historical practice of using naval pressure to secure satisfaction of claims against another State.
• Blockade of Venezuela, 1902–1903: Britain, Germany and Italy participated in coercive naval action against Venezuela over financial and other claims. The incident became an important example in discussions concerning the use of force to recover international debts and the treatment of weaker States. These incidents occurred before the adoption of the United Nations Charter and must be understood within their historical legal context.

Is Pacific Blockade Legal Under Modern International Law?

The traditional practice of imposing a naval blockade as an instrument of coercion is generally incompatible with the modern prohibition against the unlawful threat or use of force.

Article 2(4) of the United Nations Charter restricts States from using force in their international relations.

A blockade involving naval forces may fall within this prohibition even when no formal declaration of war has been made.

The United Nations General Assembly’s Resolution 3314 (XXIX) of 1974, concerning the Definition of Aggression, identifies the blockade of a State’s ports or coasts by another State’s armed forces among the acts that qualify as aggression under its framework.

However, Article 42 of the UN Charter expressly allows the Security Council to authorise military enforcement action, including blockades, where the necessary conditions are satisfied.

This creates an important distinction between a unilateral coercive blockade and a blockade undertaken pursuant to lawful Security Council authority.

The legality of a naval blockade during an armed conflict must also be assessed under the applicable rules governing the use of force and international humanitarian law.

Intervention

What Is Intervention in International Law?

Intervention means interference by one State in the internal or external affairs of another State, particularly where coercive methods are used to influence decisions that the other State is entitled to make independently.

The principle of sovereign equality recognises that every State possesses the right to determine its political, economic, social and cultural system without unlawful interference.

Intervention becomes legally problematic when one State attempts to impose its decisions upon another State through coercion.

For example, supporting armed groups to overthrow another State’s government may constitute unlawful intervention.

However, not every form of international influence, criticism or diplomatic communication amounts to prohibited intervention. The existence and nature of coercion are important considerations.

What Are the Different Types of Intervention?

Intervention may take several forms.

• Military Intervention: Military intervention involves the use of armed forces in relation to another State. It may include military operations, attacks or the deployment of armed forces without the territorial State’s valid consent. Such action must comply with the UN Charter’s rules governing the use of force.
• Political Intervention: Political intervention involves coercive interference with another State’s political independence or governmental decisions. The principle of non-intervention protects matters that fall within the sovereign freedom of States, including their choice of political system.
• Economic Intervention: Economic intervention may arise when economic measures are employed coercively to subordinate another State’s sovereign decision-making. However, ordinary economic competition, lawful trade restrictions and political pressure do not automatically constitute unlawful intervention. The legal assessment depends on the circumstances.
• Indirect Intervention: Indirect intervention may involve providing military assistance, funding or operational support to armed groups seeking to influence or overthrow another State’s government. Such conduct may violate the principle of non-intervention even where the intervening State does not directly deploy its armed forces.

What Is the Principle of Non-Intervention?

The principle of non-intervention prohibits States from coercively interfering in matters that other States are entitled to determine independently.

This principle is recognised under customary international law and reflected in several important international instruments.

The United Nations General Assembly adopted Resolution 2625 (XXV) in 1970, containing the Declaration on Principles of International Law concerning Friendly Relations and Co-operation among States.

The Declaration addresses the duty of States to refrain from intervention in the internal or external affairs of other States.

It also condemns coercive political and economic measures intended to subordinate another State’s exercise of its sovereign rights.

The Declaration is particularly important in explaining the relationship between sovereignty, political independence and non-intervention.

What Did the International Court of Justice Decide in Nicaragua v United States (1986)?

Military and Paramilitary Activities in and against Nicaragua (Nicaragua v United States of America) is one of the most important cases concerning intervention in international law.

The dispute involved activities undertaken by the United States in relation to Nicaragua, including support for the Contra forces opposing the Nicaraguan government.

In its judgment dated 27 June 1986, the International Court of Justice examined the customary international law rules governing non-intervention and the use of force.

The Court explained that the principle of non-intervention protects the right of sovereign States to conduct their affairs independently.

It recognised that prohibited intervention concerns matters in which States possess freedom of choice, including their political, economic, social and cultural systems and foreign policy.

The Court further explained that coercion is an essential element of unlawful intervention.

It held that the United States had violated obligations under customary international law, including the obligation not to intervene in Nicaragua’s affairs and the obligation not to use force against another State.

The Court also rejected the collective self-defence justification advanced by the United States in the circumstances of the case.

The judgment remains a leading authority on the meaning and legal consequences of unlawful intervention.

When Can Intervention Be Lawful?

Not every military presence or international action involving another State is necessarily unlawful.

The legality of particular conduct depends on its legal basis and the circumstances in which it occurs.

• Intervention With Valid Consent: A State may consent to the presence or assistance of another State’s armed forces within its territory. Such consent must be legally valid, and the activities undertaken must remain within its scope and comply with other applicable rules of international law.
• Security Council Authorisation: The United Nations Security Council may authorise enforcement action under Chapter VII of the UN Charter to maintain or restore international peace and security. Such action must remain within the scope of the relevant authorisation.
• Self-Defence: Article 51 of the UN Charter recognises the inherent right of individual or collective self-defence if an armed attack occurs, subject to the applicable legal requirements. Self-defence is not a general permission to interfere in another State’s internal affairs.

The legality of unilateral humanitarian intervention without Security Council authorisation or valid consent remains contested. It cannot be treated as an established general exception to the prohibition against the use of force.

Difference Between Retortion, Reprisals, Embargo, Pacific Blockade and Intervention

The five traditional compulsive methods differ in their objectives, methods and legal consequences.

What Is the Role of the United Nations in Regulating Compulsive Methods?

The establishment of the United Nations fundamentally changed the legal framework governing international disputes.

Before the UN Charter, States frequently relied on coercive diplomatic practices, economic restrictions and military pressure to pursue international claims.

Modern international law places greater emphasis on sovereign equality, peaceful settlement and collective security.

Several provisions of the UN Charter are particularly relevant.

Article 2(3): Peaceful Settlement of Disputes

Article 2(3) requires States to settle international disputes by peaceful means so that international peace, security and justice are not endangered.

The provision establishes peaceful dispute settlement as a fundamental international obligation.

Article 2(4): Prohibition Against the Use of Force

Article 2(4) prohibits the threat or use of force contrary to the Charter.

It provides the principal legal restriction on traditional armed reprisals, coercive naval blockades and unlawful military intervention.

Article 33: Peaceful Methods of Settlement

Article 33 identifies peaceful methods of settlement such as negotiation, enquiry, mediation, conciliation, arbitration, judicial settlement and resort to regional arrangements or agencies.

It places emphasis on resolving disputes through lawful procedures rather than coercive military action.

Articles 41 and 42: Security Council Enforcement Measures

Article 41 authorises non-military enforcement measures, including economic restrictions and interruption of diplomatic relations.

Article 42 allows military enforcement action where the Security Council considers measures under Article 41 inadequate or ineffective.

These provisions distinguish collective enforcement under the UN Charter from unilateral coercive action taken without a valid legal justification.

Conclusion

Compulsive means of settlement of international disputes have historically played an important role in relations between sovereign States. Retortion, reprisals, embargo, pacific blockade and intervention were traditionally employed to exert pressure, obtain compensation, secure compliance or influence another State’s conduct.

However, their legal position has changed considerably under modern international law.

Retortion remains generally permissible because it involves lawful conduct. Reprisals have largely been replaced in the law of State responsibility by the more carefully regulated concept of non-forcible countermeasures. Embargoes may be lawful depending on the applicable legal framework, while unilateral forcible blockades and unlawful intervention are restricted by the UN Charter.

The central principle is that international disputes must be addressed consistently with sovereign equality, international obligations and the prohibition against unlawful force. The contemporary international legal system therefore places primary importance on peaceful settlement and permits coercive measures only within the limits established by international law.

Note: This article was originally written by Roudro Mukhopadhyay [Student, OP Jindal Global Law School] and published on 10 January 2021. It was subsequently updated by the LawBhoomi team on 14 October 2026.