UN Peacekeeping and International Law
- Edmarverson A. Santos
- 11 minutes ago
- 34 min read
Introduction
UN peacekeeping does not rest on a single provision of the Charter of the United Nations or on a self-contained body of peacekeeping law. The Charter identifies the maintenance of international peace and security as a purpose of the Organization under Article 1(1) and assigns the Security Council primary responsibility for that function under Article 24(1), but it neither defines peacekeeping nor establishes a general legal regime for peacekeeping operations (United Nations, 1945). Peacekeeping developed through institutional practice within the Charter system and became one of the principal instruments used by the United Nations in maintaining international peace and security. In current practice, UN peacekeeping operations are deployed on the basis of Security Council mandates.
The legal basis of peacekeeping cannot be captured by assigning every operation to a single Charter chapter. Traditional peacekeeping has long been associated with Chapter VI and the peaceful settlement of disputes, although the Security Council has not relied on Chapter VI as a formal legal classification when establishing such operations. The Council has increasingly invoked Chapter VII when authorizing missions in volatile settings, particularly where stronger powers are considered necessary. A Chapter VII mandate does not, by itself, transform a peacekeeping operation into peace enforcement. The authority and character of an operation depend on the relevant Security Council resolutions, the powers they confer, the role of consent, and the circumstances in which the mandate is implemented (United Nations, 2008).
The place of early peacekeeping within the Charter system was considered indirectly by the International Court of Justice in Certain Expenses of the United Nations. The Court was not asked to formulate a general doctrine governing the legality of peacekeeping. It held that expenditures relating to the United Nations Emergency Force and the United Nations Operation in the Congo constituted “expenses of the Organization” within Article 17(2) because they had been incurred in carrying out the purposes of the United Nations (ICJ, 1962). The advisory opinion is significant because the Court accepted that operations not expressly described in the Charter could nonetheless serve the Organization’s Charter purposes.
Peacekeeping practice subsequently developed around three basic principles: consent of the parties, impartiality, and the non-use of force except in self-defense and defense of the mandate (United Nations, 2008). These principles help define the institutional character of peacekeeping, but they do not constitute an exhaustive legal code. Consent may operate as an essential condition for a peacekeeping relationship and, where deployment rests on host-state agreement, as part of the legal basis for the mission’s presence. Security Council resolutions establish mandated tasks and powers, while rules of engagement regulate the circumstances and manner in which military personnel may exercise authorized force. Status of forces agreements address the mission’s legal position in the host state, including privileges and immunities, freedom of movement, communications, facilities, and jurisdictional arrangements (UN Secretary-General, 1990).
The conduct of peacekeeping operations may also engage international human rights law, international humanitarian law, international criminal law, and rules of international responsibility. The applicable legal rules cannot be identified solely from the mission’s designation. International humanitarian law, in particular, does not apply to UN forces merely because they are deployed in territory affected by armed conflict. Whether the United Nations, troop-contributing states, or both become parties to an armed conflict depends on the ordinary legal criteria governing the classification of armed conflicts and on the forces’ actual involvement in hostilities (ICRC, 2025).
For forces operating under United Nations command and control, the Secretary-General’s 1999 Bulletin sets out fundamental principles and rules of international humanitarian law. Its field-of-application provision states that those rules apply when UN forces, in situations of armed conflict, are actively engaged as combatants, to the extent and for the duration of that engagement (UN Secretary-General, 1999). The Bulletin is an important institutional instrument, but it does not exhaust the wider legal questions concerning the application of humanitarian law to international organizations, participating states, and multinational forces.
UN peacekeeping is consequently governed through a layered legal structure rather than by a single treaty, Charter chapter, or institutional doctrine. Determining the legality of a mission or of particular conduct requires identifying the source and limits of the operation’s authority, the legal significance of consent, the terms of applicable status arrangements, the rules governing the use of force, and the international legal obligations engaged by conduct in the field. That structure has allowed peacekeeping to accommodate missions with markedly different mandates and functions, while preserving the need to identify the legal basis for each power exercised.
1. Peacekeeping as a Practice Under the UN Charter
Peacekeeping was not among the mechanisms expressly described in the Charter of the United Nations. The Charter nevertheless created institutions with broad responsibilities for international peace and security rather than an exhaustive catalogue of operational techniques. Article 24 confers primary responsibility for maintaining international peace and security on the Security Council, while the Council’s specific powers are distributed principally across Chapters VI, VII, VIII, and XII. Article 29 separately permits the Council to establish subsidiary organs necessary for the performance of its functions (United Nations, 1945).
These provisions perform different legal functions. Article 29 supplies an organizational power; it does not independently determine the substantive authority that a peacekeeping mission may exercise. The powers of a Council-established operation must be traced through the Charter responsibilities being exercised and the Security Council resolutions defining the mission. Peacekeeping consequently developed within the Charter system without acquiring a single constitutional basis applicable in identical terms to every operation.
The International Court of Justice’s advisory opinion in Certain Expenses of the United Nations supports this understanding. The Court was not asked to recognize a general implied power to conduct peacekeeping. It held that expenditures relating to the United Nations Emergency Force and the United Nations Operation in the Congo constituted “expenses of the Organization” under Article 17(2) because they had been incurred to carry out purposes of the United Nations (ICJ, 1962). The reasoning demonstrates that an operational method need not be expressly named in the Charter before activities undertaken through that method can fall within the Organization’s functions.
Peacekeeping developed largely through this combination of Charter authority and institutional practice. Early operations created precedents concerning observation, interposition, consent, command, financing, and restrictions on force. Later missions retained elements of that practice while assuming functions that the first operations had never been designed to perform. Legal analysis of modern peacekeeping must consequently begin with the particular mandate and circumstances rather than with a fixed model derived from the earliest missions.
1.1 From Observation Missions to Multidimensional Operations
United Nations peacekeeping began in 1948 with the deployment of military observers in the Middle East under what became the United Nations Truce Supervision Organization. UNTSO was designed around observation and reporting rather than coercion. Similar early operations sought to monitor ceasefires, supervise agreements, reduce the risk of renewed hostilities, and create political space in which disputes could be addressed through negotiation and other peaceful means (United Nations Peacekeeping, 2026).
The First United Nations Emergency Force marked an important development in 1956. Created in response to the Suez Crisis, UNEF I was the first armed UN peacekeeping force and introduced an interposition function substantially different from unarmed observation. Its troops were deployed to help secure and supervise the cessation of hostilities and the withdrawal of foreign forces, but they were not established to impose a political settlement through military defeat of a belligerent.
Traditional peacekeeping consequently relied on a relatively limited military conception. Forces monitored agreements, separated opposing sides, reported violations, and helped stabilize conditions while political actors pursued a settlement. Their presence was intended to support diplomacy rather than replace it.
The range of peacekeeping functions expanded sharply after the Cold War as missions were increasingly deployed in states emerging from internal armed conflicts and political collapse. Multidimensional operations combined military and police components with substantial civilian functions. Security Council mandates came to encompass implementation of comprehensive peace agreements, disarmament and demobilization, electoral assistance, human-rights monitoring, security-sector reform, rule-of-law assistance, and support for the restoration of state authority (United Nations, 2008).
That transformation altered the legal questions confronting peacekeeping. A mission limited to observing a ceasefire does not exercise the same functions as one protecting civilians, assisting national police, supporting elections, monitoring detention, or helping extend state authority. The legal assumptions associated with lightly armed interposition forces cannot by themselves explain the mandates, powers, and restraints of contemporary operations.
1.2 Peacekeeping Within the UN Peace and Security System
Peacekeeping forms part of a broader system of United Nations activity concerned with preventing, managing, and resolving conflict. Preventive diplomacy seeks to prevent disputes from escalating into violence or to contain existing tensions. Peacemaking is directed toward bringing parties in conflict toward agreement through diplomatic means. Peacebuilding addresses conditions that affect the durability of peace, including institutional capacity, rule of law, security-sector governance, and political reconciliation (United Nations, 2008).
Peacekeeping occupies a different position. It is generally used to preserve a fragile peace, stabilize a situation after hostilities have been halted, or assist implementation of agreements reached through political processes. Modern missions may perform substantial peacebuilding functions, but the overlap does not erase the conceptual distinction between deploying an operation to maintain peace and pursuing longer-term measures intended to prevent renewed conflict.
Peace enforcement is separated more clearly by the role of coercion and consent. UN doctrine uses the term for coercive action authorized by the Security Council to maintain or restore international peace and security where consent of the principal parties is not required. Robust peacekeeping, by contrast, may involve significant force at the tactical level while continuing to operate within a peacekeeping framework based on Security Council authorization and consent of the host state or main parties (United Nations, 2008; United Nations Peacekeeping, 2026).
These categories describe different functions rather than sealed compartments. A multidimensional operation may combine peacekeeping with political mediation and peacebuilding tasks, while a deteriorating security situation may increase pressure for coercive action. The distinction remains legally significant because consent, the source of authority, and the level at which force is employed affect whether an operation remains peacekeeping or moves toward enforcement.
2. The Legal Authority to Establish Peacekeeping Operations
The Security Council’s authority to establish a peacekeeping operation begins with Article 24 of the Charter, under which Member States confer on it primary responsibility for maintaining international peace and security. Article 24(2) requires the Council to act consistently with the purposes and principles of the United Nations and identifies Chapters VI, VII, VIII, and XII as containing specific powers for the performance of those duties (United Nations, 1945).
Peacekeeping is not assigned wholesale to any one of those chapters. The Council responds to particular situations through resolutions that establish, renew, modify, or terminate operations and define their mandates. The relevant legal inquiry concerns the Charter powers engaged by the Council, the terms of its decisions, and the authority actually entrusted to the mission.
This avoids an artificial constitutional classification. Traditional peacekeeping has commonly been associated with Chapter VI, whereas many later operations have been authorized in resolutions invoking Chapter VII. UN peacekeeping doctrine itself warns that attaching a mission to a particular Charter chapter may obscure the tasks and powers that the Council has actually assigned to it (United Nations, 2008).
2.1 Security Council Authority and Charter Powers
Chapter VI provides powers relating to the pacific settlement of disputes. It permits the Security Council to investigate disputes or situations, call upon parties to settle disputes peacefully, recommend appropriate procedures, and propose terms of settlement. Traditional consensual peacekeeping developed alongside these functions, which explains the familiar description of such missions as “Chapter VI” operations.
That description is not a formal Charter category. No provision of Chapter VI creates peacekeeping forces, and current UN guidance records that the Security Council need not identify a Charter chapter when authorizing a peacekeeping operation and has not formally invoked Chapter VI as the basis for establishing one (United Nations Peacekeeping, 2026). The content of the resolution remains more important than the informal label.
Chapter VII becomes relevant once the Council determines under Article 39 that there is a threat to the peace, breach of the peace, or act of aggression. The Charter then provides for measures under Articles 41 and 42 directed toward maintaining or restoring international peace and security. In contemporary practice, the Council has frequently invoked Chapter VII when authorizing peace operations in volatile post-conflict settings, including situations in which national authorities cannot maintain security and public order (United Nations Peacekeeping, 2026).
Chapter VII authority does not automatically make an operation a peace-enforcement mission. A peacekeeping operation may receive substantial coercive powers while continuing to rely on consent and to function within the institutional principles of peacekeeping. Peace enforcement differs principally in permitting coercive action without dependence on the consent of the main parties in the same way.
The legal character of a mission is consequently determined by more than the presence or absence of the words “Chapter VII.” The operative terms of the Council’s resolution, the tasks assigned, the authority to use force, the continuing role of consent, and later modifications to the mandate are all relevant to understanding the powers of the operation.
2.2 The General Assembly and the Early Practice
The Security Council occupies the central position in contemporary UN peacekeeping, but the General Assembly contributed significantly to its early development. The Suez Crisis of 1956 provided the decisive example. With the Security Council unable to resolve the crisis because of disagreement involving permanent members, the General Assembly convened its first emergency special session.
The legal and institutional development of UNEF I occurred through a sequence of Assembly decisions. Resolution 998 (ES-I) of 4 November 1956 requested the Secretary-General to submit a plan for an emergency international UN force. Resolution 1000 (ES-I) of 5 November established a United Nations Command for the emergency force, and resolution 1001 (ES-I) of 7 November approved the guiding arrangements for organizing and deploying the Force (UN General Assembly, 1956a; 1956b; 1956c).
UNEF I was not an enforcement operation imposed on Egypt. Its deployment and continued presence rested on Egyptian consent, while the Force was prohibited from treating that consent as authority to conduct coercive military action against the territorial state. The arrangement helped establish consent as a defining feature of the early peacekeeping model.
The constitutional position of the General Assembly was later considered in Certain Expenses. The International Court of Justice rejected the proposition that the Security Council’s responsibility under Article 24 excluded all General Assembly competence in matters of international peace and security. The Court characterized the Council’s responsibility as primary rather than exclusive, while distinguishing the Assembly’s functions from coercive enforcement action reserved to the Security Council under the Charter system (ICJ, 1962).
The UNEF precedent consequently demonstrates both the Assembly’s historical contribution and the limits of the analogy with modern Council-created missions. It does not establish a general General Assembly power equivalent to the Security Council’s contemporary practice of creating operations and conferring coercive authority through binding decisions.
3. Peacekeeping Mandates and the Scope of Mission Authority
A peacekeeping mandate gives legal and operational content to the decision establishing or continuing a mission. The designation “peacekeeping operation” does not itself confer a standard package of powers. Security Council resolutions identify what a mission is expected or authorized to do, and those functions differ according to the conflict, political settlement, security conditions, and institutional needs of the situation concerned.
Mandates may require a mission to monitor ceasefires, assist implementation of comprehensive peace agreements, protect civilians, support disarmament and demobilization, provide electoral assistance, contribute to security-sector and rule-of-law reform, monitor human rights, or assist the restoration and extension of state authority. These functions illustrate the breadth of contemporary UN peacekeeping rather than a set of powers belonging automatically to every operation (United Nations Peacekeeping, 2026).
The creation of a mission, assignment of a task, and authorization of particular means remain separate questions. A Security Council decision may establish an operation and instruct it to protect civilians, for example, without leaving the permissible methods of protection undefined. The resolution must be read to determine whether and under what conditions coercive measures may be used to perform that task.
3.1 Interpreting Security Council Mandates
The operative text of the relevant Security Council resolutions is the starting point for determining mission authority, but individual provisions cannot always be interpreted in isolation. A mandate may be distributed across several paragraphs dealing separately with priorities, tasks, geographical limits, use of force, cooperation with national authorities, and reporting requirements.
The International Court of Justice has recognized that interpretation of Security Council resolutions requires close attention to their terms and context. In the Namibia advisory opinion, the Court stated that the legal consequences of a Council resolution must be determined with reference to its language, the discussions leading to its adoption, the Charter provisions invoked, and the surrounding circumstances (ICJ, 1971, para. 114). In the Kosovo advisory opinion, it added that interpretation may also require consideration of statements made by Council members, other resolutions concerning the same issue, and subsequent practice of relevant UN organs and affected states (ICJ, 2010, para. 94).
Peacekeeping mandates also change over time. The Council commonly renews missions while modifying their priorities, authorized strength, geographical focus, or powers. A mission originally created for one purpose may acquire substantially different responsibilities through later resolutions. Current authority must consequently be identified from the applicable mandate as it has evolved, not merely from the resolution that first created the operation.
Expressions such as “all necessary measures” or “all necessary means” can authorize significant coercive action, but their legal effect remains tied to the provision in which they appear. Such language does not create unrestricted military authority. The object of the authorization, geographical scope, protected persons or activities, conditions imposed by the Council, and other applicable international law continue to delimit what may lawfully be done.
3.2 Mandates, Rules of Engagement, and Operational Authority
The Security Council mandate and mission-specific rules of engagement operate at different levels. The Council defines the institutional functions and authority of the operation. Rules of engagement for the military component translate available authority into operational directions governing when different levels of force may be employed, how that force may be used, and which command authorizations are required (United Nations, 2008).
Rules of engagement are legally and operationally significant, but they cannot create Security Council powers that the mission does not possess. Their function is to regulate the exercise of force within the authority available under the mandate and other applicable legal rules. They may impose operational restrictions or procedural requirements without enlarging the institutional competence of the mission.
The distinction becomes particularly important in civilian-protection mandates. A Council resolution may authorize a mission to use force to protect civilians under specified conditions. The rules of engagement then provide more detailed guidance for military personnel confronting situations in which that authority may be exercised. Neither level answers every question independently of the other.
Authority must also be distinguished from capacity. A mission can possess legal authority to protect civilians while lacking sufficient personnel, mobility, intelligence, equipment, or access to respond effectively in every location. Operational weakness may explain a failure to act, but it does not alter the scope of the authority conferred by the Security Council.
Police components operate through a related institutional framework. UN doctrine uses Directives on the Use of Force for police components alongside Rules of Engagement for military components (United Nations, 2008). Treating either instrument as if it were the Security Council mandate itself would obscure both the source of mission authority and the internal mechanisms governing its exercise.
4. UN Peacekeeping Principles
Consent, impartiality, and the non-use of force except in self-defense and defense of the mandate remain the three basic principles of United Nations peacekeeping. They emerged through practice and were consolidated in UN doctrine as the features distinguishing peacekeeping from other forms of international security action (United Nations, 2008; United Nations Peacekeeping, 2026).
Their legal character requires care. The triad is not stated in the Charter as a set of treaty obligations, and its inclusion in UN doctrine does not by itself establish each element as an autonomous rule of customary international law. The principles function primarily as institutional standards governing the design, legitimacy, and operation of peacekeeping missions.
They also interact. Erosion of consent can restrict access and freedom of movement; coercive action can affect perceptions of impartiality; and impartial implementation of a mandate may require measures against a party obstructing a peace agreement or threatening civilians. Modern peacekeeping depends less on applying each principle in isolation than on maintaining their relationship under difficult operational conditions.
4.1 Consent and the Legal Basis for Presence
Consent of the main parties is a defining principle of UN peacekeeping. It signifies acceptance of the political process and of an international operation established to support that process. Without sufficient consent, a mission risks becoming a party to the conflict or moving toward coercive enforcement rather than peacekeeping (United Nations, 2008).
The consent of the “main parties” and the consent of the host state address related but different questions. In an internal conflict, agreement from significant armed groups may be essential to the political and operational viability of a mission. Host-state consent has a distinct legal significance where a consensual operation relies on that consent for its presence and activities on national territory.
That proposition does not apply to every international military presence authorized by the Security Council. Chapter VII enforcement authority may permit coercive measures without host-state consent. Such an operation, however, raises a different legal relationship and cannot simply be treated as traditional consensual peacekeeping.
Consent may also weaken without being formally withdrawn. A government or another principal party can continue publicly to accept a mission while denying access, restricting patrols, withholding clearances, obstructing investigations, or preventing contact with relevant communities. UN doctrine recognizes that sufficiently serious restrictions on freedom of action may amount in practice to a de facto withdrawal of consent (United Nations, 2008).
National consent does not guarantee cooperation at the local level. Armed groups may fragment, commanders may disregard political agreements, and local actors may resist the mission despite acceptance by national leadership. A peacekeeping operation may retain a lawful basis for deployment while confronting persistent obstruction in particular areas. The distinction between formal consent and operational cooperation is indispensable to understanding contemporary missions.
4.2 Impartiality Without Political Neutrality
Impartiality requires a mission to apply its mandate according to the conduct and obligations of the parties rather than according to political preference. It does not require identical treatment of actors behaving differently. A party complying with a ceasefire is not in the same position as one attacking civilians, blocking humanitarian access, or forcibly obstructing implementation of the mandate.
UN peacekeeping doctrine consequently rejects the equation of impartiality with passivity. The mission may respond differently to different parties when their conduct warrants different responses under the mandate. Refusing to act against a serious breach merely to preserve superficial symmetry can undermine rather than protect impartial implementation (United Nations, 2008).
The principle still limits mission behavior. Action directed against one party requires a mandate-based justification and should be grounded in objectively identifiable conduct. If a mission appears to pursue the political or military objectives of one side independently of its mandate, its credibility and the consent on which peacekeeping depends may deteriorate.
Impartiality is consequently compatible with differentiated action but not with partisanship. Its function is to preserve fidelity to the mandate and the peace process while allowing the mission to respond to violations that threaten either.
4.3 The Use of Force in Peacekeeping
The original armed peacekeeping model placed strict limits on force. Beginning with UNEF I, self-defense was treated as the central exception to non-use. UN practice later developed a broader operational conception under which peacekeepers could resist forcible efforts to prevent them from carrying out Security Council-mandated duties (United Nations Office of Legal Affairs, 1993).
This peacekeeping conception of self-defense must be distinguished carefully from the classic interstate application of Article 51 of the Charter without suggesting that Article 51 is irrelevant to the United Nations. The UN Office of Legal Affairs has stated that self-defense is recognized under customary international law and Article 51 and is not confined to states; the United Nations itself may invoke an inherent right of self-defense. Peacekeeping practice developed an additional operational dimension by recognizing resistance to forcible obstruction of the mandate as falling within the permissible use of force (United Nations Office of Legal Affairs, 1993).
Current UN doctrine expresses the peacekeeping principle as non-use of force except in self-defense and defense of the mandate. Security Council resolutions may authorize force at the tactical level for purposes extending beyond immediate protection of peacekeepers, including protection of civilians and resistance to forcible interference with mandated activities. The precise authority available in any mission depends on the wording of its mandate and the accompanying operational framework.
Robust peacekeeping remains distinct from peace enforcement. The former may employ substantial force at the tactical level while retaining Security Council authorization and the consent central to peacekeeping. Peace enforcement can involve coercive military action at the strategic or international level without the consent of the principal parties (United Nations, 2008; United Nations Peacekeeping, 2026).
Authorization to use force does not determine how every use of force may lawfully be conducted. UN doctrine requires force in peacekeeping to be used with restraint, as a last resort where other approaches are inadequate, and in a manner calibrated to the legitimate operational objective. The amount of force employed should not exceed what is reasonably required to achieve that objective, while any applicable rules of international humanitarian law, human-rights law, and other international law remain independently relevant to the conduct of the mission.
5. Robust Peacekeeping and Peace Enforcement
The expansion of Security Council mandates has reduced the practical distance between peacekeeping and enforcement without eliminating the distinction between them. United Nations doctrine uses “robust peacekeeping” for operations authorized to use force at the tactical level in self-defense or defense of the mandate while continuing to operate on the basis of the consent associated with peacekeeping. Peace enforcement differs because it permits coercive measures without requiring the consent of the main parties and may involve military force at the strategic or international level (United Nations, 2008).
These categories are not separate legal regimes created by the Charter. Chapter VII provides the Security Council with authority to adopt coercive measures, but invocation of that chapter does not by itself determine whether an operation is peacekeeping or peace enforcement. The Council has repeatedly authorized peacekeeping missions under Chapter VII while retaining consent, impartiality, and restricted recourse to force as elements of their institutional framework.
The boundary becomes harder to maintain when peacekeepers receive authority to act proactively against armed groups rather than merely respond to attacks on personnel. Protection of civilians, prevention of forcible obstruction, and defense of mandated activities may require substantial military force. The intensity of an engagement does not alone determine the character of the wider operation; the mandate, purpose of the force, role of consent, and level at which coercion is employed remain central.
Significant force can nonetheless affect the foundations on which peacekeeping depends. Operations directed against one armed actor may face accusations of partiality or a deterioration of cooperation even where their actions fall within the Security Council mandate. Robust peacekeeping consequently tests the proposition that coercion can remain compatible with peacekeeping when force serves the mandate rather than an independent strategy of imposing a settlement through military compulsion.
5.1 Tactical Force and Strategic Coercion
The reference to tactical force concerns the level at which coercive authority is exercised, not merely the weapons used or the severity of a particular encounter. A contingent may engage in intense combat during a specific operation while the mission’s wider purpose remains protection of civilians, defense of a political process, or implementation of other mandated tasks. UN doctrine contrasts this with peace enforcement, where coercive action may be undertaken at the strategic or international level without the consent of the principal parties (United Nations, 2008).
Security Council authorization remains decisive for determining what a mission may do, but the mere use of Chapter VII is insufficient to classify the operation. A resolution may authorize “all necessary measures” for particular purposes and still preserve features associated with peacekeeping. The wording, scope, objectives, territorial limits, and conditions of the authorization must be examined in the context of the mandate as a whole.
Authority to use force also differs from the law governing the manner in which force is exercised. A Security Council resolution may authorize coercive action, while international humanitarian law governs military conduct if the requirements for its application are satisfied. In situations governed instead by a law-enforcement paradigm, applicable human-rights standards impose a different framework for the use of force. Authorization and conduct remain separate legal inquiries.
5.2 The Force Intervention Brigade
The Force Intervention Brigade established within MONUSCO in 2013 is the clearest institutional example of the pressure that offensive mandates can place on the traditional peacekeeping model. Acting under Chapter VII, the Security Council created the Brigade through Resolution 2098 and described the measure as exceptional, specifying that it was not intended to establish a precedent or prejudice the agreed principles of peacekeeping (UN Security Council, 2013).
The Brigade operated under the direct command of the MONUSCO Force Commander and was authorized to conduct targeted offensive operations, either unilaterally or jointly with the armed forces of the Democratic Republic of the Congo. Its mandate included preventing the expansion of armed groups, neutralizing them, and contributing to their disarmament. These tasks went well beyond observation, interposition, or the reactive defense traditionally associated with peacekeeping.
Resolution 2098 nevertheless kept the Brigade within MONUSCO and required compliance with international law, including international humanitarian law. Its mandate placed particular strain on impartiality because UN forces could undertake offensive action against identified armed groups while cooperating with the territorial government. Impartiality in that setting could not mean military equidistance; it depended on disciplined implementation of the Security Council mandate rather than pursuit of an independent partisan objective.
The Brigade also illustrates why a mandate authorizing offensive operations does not by itself determine the status of UN forces under international humanitarian law. Party status depends on the factual involvement of the relevant forces and the ordinary criteria governing armed conflicts. Once those conditions are met, an institutional designation as a peacekeeping force cannot prevent the applicable rules of armed conflict from governing its operations.
6. Status of Forces Agreements and Legal Presence
Security Council authorization establishes the mandate of a peacekeeping operation, but it does not ordinarily settle all legal conditions governing the mission’s presence in the territorial state. Status of forces agreements address this separate relationship. They regulate the conditions under which the United Nations and its personnel can enter, remain, move, communicate, operate facilities, and perform assigned functions within the host state.
SOFAs commonly deal with privileges and immunities, freedom of movement, communications, premises, entry and departure, identification, claims, and civil or criminal jurisdiction. These provisions have immediate operational consequences. A mission may possess extensive authority under its Security Council mandate yet encounter serious obstacles if personnel cannot move freely, communications are restricted, or equipment and facilities cannot be used as contemplated.
The mandate and the status agreement consequently perform different functions. The former establishes and defines institutional authority. The latter regulates many of the legal conditions under which the operation exercises that authority within the host state. Neither can be treated as a substitute for the other.
6.1 The Model SOFA and Mission-Specific Agreements
The Secretary-General submitted the Model Status-of-Forces Agreement for Peacekeeping Operations to the General Assembly in 1990. Document A/45/594 consolidated established practice into a model for agreements between the United Nations and states hosting peacekeeping operations. Its provisions were designed to be adapted where the circumstances of a particular mission required different arrangements (UN Secretary-General, 1990).
The Model SOFA is not itself a treaty automatically applicable to every peacekeeping operation. Its provisions acquire legal significance through mission-specific agreements or other arrangements governing a particular deployment. Security Council practice has also provided in some cases for the provisional application of model status arrangements pending conclusion of a specific agreement with the host government.
The Model SOFA operates alongside Article 105 of the Charter and the 1946 Convention on the Privileges and Immunities of the United Nations. Different categories of personnel have different legal statuses. UN officials, experts on mission, members of national military contingents, civilian personnel, and other participants cannot be assumed to possess identical immunities or be subject to the same jurisdictional rules (United Nations, 1946; UN Secretary-General, 1990).
Status arrangements preserve the institutional independence required for the mission to function, but they do not place peacekeeping personnel wholly outside the legal order of the host state. The Model SOFA requires members of the operation to respect local laws and regulations while protecting the United Nations against interference incompatible with the independent performance of its functions.
6.2 The UN, Host State, and Troop-Contributing States
National military contingents create a triangular legal relationship among the United Nations, the host state, and troop-contributing states. Personnel supplied by Member States remain organs of those states while being placed at the disposal of the United Nations for the peacekeeping operation. For assigned tasks they fall under United Nations operational control, but they are not transferred into United Nations national command. Contributing states retain national command and specified powers over their personnel (United Nations, 2008).
That distinction is particularly important for discipline and criminal jurisdiction. Under paragraph 47(b) of the Model SOFA, military members of national contingents are subject to the exclusive criminal jurisdiction of their respective participating states for offenses committed in the host country. The host state does not obtain criminal jurisdiction over those personnel merely because the alleged offense occurred on its territory (UN Secretary-General, 1990).
Other aspects of authority are distributed differently. Operational direction may pass through the UN Force Commander, while the contributing state retains disciplinary authority, criminal jurisdiction, and the power to withdraw its contingent. National limitations and instructions may also affect how a contingent operates. The coexistence of these forms of authority later becomes central to determining whether particular conduct is attributable to the United Nations, the contributing state, or both.
7. International Law Governing Peacekeeping Conduct
A Security Council mandate establishes institutional authority but does not constitute the entire law governing a peacekeeping operation. Different legal regimes become relevant according to the actor involved, the function being performed, and conditions in the field. The Charter, status agreements, privileges and immunities, international humanitarian law, human-rights law, international criminal law, and rules of international responsibility address different dimensions of peacekeeping conduct.
This is particularly significant when a mission has coercive powers. Security Council authorization may determine that an operation can undertake a particular task, but it does not eliminate the separate question of how that task may lawfully be performed. Military action against an armed group, crowd control, detention, policing, electoral assistance, and human-rights monitoring do not necessarily engage the same legal rules.
The applicable obligations may also differ among participants in the same operation. The United Nations possesses international legal personality, while military and police personnel are supplied by states that remain subject to international obligations of their own. The presence of several legal actors within one institutional operation makes it necessary to identify both the relevant rule and the entity to which that rule applies.
7.1 Human Rights in Peacekeeping Operations
Human-rights functions are embedded in many contemporary peacekeeping mandates. Missions may monitor and report violations, protect civilians, support human-rights institutions, assist national police, strengthen justice and corrections systems, or contribute to broader rule-of-law programs. UN peacekeeping doctrine accordingly places international human-rights law within the normative framework relevant to operations (United Nations, 2008).
The source of a particular obligation still requires separate analysis. The United Nations is not a state party to the principal human-rights treaties, so it cannot simply be treated as treaty-bound in precisely the same manner as a Member State. Charter obligations, customary international law, mission mandates, institutional rules, and obligations applicable to participating states may each affect peacekeeping conduct.
Treaty obligations of troop-contributing states can present additional questions when personnel act outside national territory. Whether a particular human-rights treaty applies extraterritorially depends on the jurisdiction clause, interpretation, and jurisprudence of the treaty regime concerned. No single factual-control test governs every international or regional human-rights instrument.
United Nations policies may impose further institutional requirements without acquiring the status of treaties. The Human Rights Due Diligence Policy on United Nations Support to Non-United Nations Security Forces requires the Organization to assess the human-rights risks associated with such support and to withhold or suspend assistance where the conditions established by the policy are met. It is intended to prevent UN support from contributing to grave violations of international humanitarian, human-rights, or refugee law (UN Secretary-General, 2013).
7.2 When International Humanitarian Law Applies
The presence of peacekeepers in a state affected by armed conflict does not automatically make the United Nations or participating contingents parties to that conflict. Personnel may perform observation, political, police, protection, or logistical functions without becoming participants in the hostilities. The existence of an armed conflict in the territorial state and the legal position of the peacekeeping mission within that conflict are separate questions.
International humanitarian law becomes applicable when its objective conditions are satisfied. International armed conflicts are governed by the criteria reflected in common Article 2 of the Geneva Conventions. For non-international armed conflicts, international jurisprudence has treated the intensity of the violence and the organization of the non-state armed party as central requirements (ICTY, 1995). Neither a Security Council mandate nor the invocation of Chapter VII displaces those classification criteria.
For forces under United Nations command and control, the Secretary-General’s 1999 Bulletin constitutes an internal legal instrument of the Organization setting out fundamental principles and rules of international humanitarian law. Its field-of-application provision states that those rules apply when UN forces are actively engaged as combatants in an armed conflict, to the extent and for the duration of their engagement (UN Secretary-General, 1999).
The Bulletin addresses protection of civilians, means and methods of combat, treatment of detained persons, protection of the wounded and sick, and medical and relief activities. It is not a treaty and does not provide an exhaustive account of all humanitarian-law obligations potentially applicable to the United Nations, troop-contributing states, or individual personnel. Nor does the fact that the United Nations is not a party to the Geneva Conventions place UN forces outside international humanitarian law.
Multinational involvement in an existing non-international armed conflict can raise harder questions of party status. The ICRC has advanced a support-based approach under which an international organization or state may become a party when it makes a direct and effective contribution to the collective conduct of hostilities in support of an existing party. The ICRC presents this approach as supplementing the ordinary classification analysis in appropriate support relationships; it is an interpretive position rather than an uncontested treaty rule (ICRC, 2025).
7.3 Peacekeepers as Parties to an Armed Conflict
When UN forces themselves become a party to an armed conflict, international humanitarian law governs their military operations against the opposing party for as long as the relevant legal conditions continue. The Charter legitimacy of the mission does not alter this conclusion. The law governing authorization to use force and the law regulating conduct during armed conflict address different legal questions.
Applicable rules include distinction between military objectives and civilian persons or objects, the prohibition of indiscriminate attacks, proportionality, precautions in attack, and the treatment of persons who are wounded, detained, captured, or otherwise in the power of a party. The precise treaty rules differ according to whether the conflict is international or non-international, while customary international humanitarian law supplies additional obligations.
Peacekeeping personnel also benefit from a specific treaty regime. The 1994 Convention on the Safety of United Nations and Associated Personnel requires states parties to criminalize specified attacks against qualifying UN and associated personnel and establishes protections for covered operations. Its scope is not unlimited. Article 2(2) excludes a United Nations operation authorized by the Security Council as an enforcement action under Chapter VII in which personnel are engaged as combatants against organized armed forces and the law of international armed conflict applies (United Nations, 1994).
International humanitarian and international criminal law contain related protections. The Rome Statute criminalizes intentionally directing attacks against personnel, installations, material, units, or vehicles involved in qualifying peacekeeping missions in both international and non-international armed conflicts, provided that they are entitled to the protection given to civilians or civilian objects under the law of armed conflict (Rome Statute, 1998, arts. 8(2)(b)(iii), 8(2)(e)(iii)).
The protection is conditional because international humanitarian law distinguishes between different forms of participation in hostilities. An individual civilian loses protection against direct attack only for such time as that person directly participates in hostilities. Where a UN military force itself becomes a party to an armed conflict, the legal position of its military personnel is assessed under the rules applicable to members of the armed forces of a party or their equivalent status in the relevant conflict classification. The fact that personnel wear UN insignia does not independently preserve civilian protection once the applicable rules make them lawful military targets.
8. Attribution, Responsibility, and Accountability
“Accountability” in peacekeeping encompasses several legally distinct questions. Attribution determines whether conduct is regarded as the act of the United Nations, a contributing state, or another actor. International responsibility requires both attributable conduct and breach of an international obligation. Immunity concerns whether a particular jurisdiction may exercise legal process, while disciplinary responsibility and individual criminal liability operate through still different rules.
These concepts cannot be substituted for one another. Immunity does not make otherwise unlawful conduct lawful. Attribution to the United Nations does not establish the elements of an individual criminal offense, and criminal responsibility of a peacekeeper does not necessarily establish that the Organization has committed an internationally wrongful act.
Peacekeeping makes these distinctions unusually difficult because national forces remain connected to their states while operating under United Nations operational control. Formal command arrangements, actual instructions, retained national powers, and the circumstances of the specific act can point toward different legal conclusions.
8.1 Attribution Between the UN and Contributing States
The International Law Commission’s 2011 Articles on the Responsibility of International Organizations are the most developed general codification project dealing with attribution and responsibility of international organizations. They were adopted by the ILC and taken note of by the General Assembly, but they have not entered into force as a treaty, and the customary status of individual provisions cannot be assumed uniformly (ILC, 2011).
Article 7 addresses a state organ placed at the disposal of an international organization. Conduct is attributed to the organization where it exercises effective control over the conduct concerned. The accompanying commentary treats national contingents in UN peacekeeping as an important example because contributing states retain some governmental powers while operational authority for assigned functions is exercised through the United Nations.
United Nations practice has traditionally emphasized the institutional character of a peacekeeping force operating under UN authority. Such a force has been treated as a subsidiary organ of the Organization, with the United Nations accepting responsibility toward third parties for conduct arising from peacekeeping operations under its effective command and control. The ILC’s focus on effective control over the particular conduct, however, has directed attention toward the actual allocation and exercise of authority rather than formal institutional characterization alone (ILC, 2011).
Judicial practice shows that attribution may depend heavily on the facts. In State of the Netherlands v. Nuhanović, the Supreme Court of the Netherlands upheld attribution of specified Dutchbat conduct to the Netherlands and rejected the proposition that international law necessarily excludes attribution of the same conduct to more than one actor (Supreme Court of the Netherlands, 2013). The judgment demonstrates the possibility of state attribution within a UN operation without establishing a general presumption of dual attribution.
The resulting law remains contested in important respects. Formal placement of troops within a UN operation, national command powers, operational control, specific instructions, and the capacity to prevent the disputed conduct may carry different weight depending on the circumstances. Attribution cannot safely be determined from the institutional label of the mission alone.
8.2 Institutional Responsibility for Wrongful Conduct
Attribution is only the first stage of responsibility. Under the ILC framework, an internationally wrongful act of an international organization requires conduct attributable to that organization and conduct that breaches an international obligation binding upon it (ILC, 2011). The parallel law of state responsibility requires the same basic separation between attribution and breach.
The capacity of the United Nations to possess international rights and duties follows from its international legal personality. In Reparation for Injuries, the International Court of Justice held that the Organization possesses international personality and capacities necessary for performing its functions (ICJ, 1949). The later law of responsibility, rather than that advisory opinion itself, supplies the framework for determining when conduct attributable to the Organization can produce international responsibility.
A contributing state may incur responsibility separately where conduct attributable to it breaches one of its own international obligations. Responsibility of the United Nations and responsibility of a state are not mutually exclusive as a matter of principle, but neither can be inferred merely because both actors participated in the same mission. Attribution and breach must be established for each entity under the rules applicable to it.
Concurrent involvement can consequently produce several possible legal configurations. Conduct may be attributable to the United Nations, to a state, or in appropriate circumstances to more than one actor. Even where attribution overlaps, the obligations binding each actor and the legal consequences of breach may differ.
8.3 Immunity, Jurisdiction, and Individual Accountability
Privileges and immunities protect the independent performance of United Nations functions; they do not provide substantive authorization for unlawful conduct. Article 105 of the Charter, the 1946 Convention on the Privileges and Immunities of the United Nations, and applicable status agreements provide different protections for different categories of personnel. The precise legal status of an official, expert on mission, military contingent member, or other participant must be identified before questions of jurisdiction can be answered (United Nations, 1945; United Nations, 1946).
Military members of national contingents occupy a distinct position under the Model SOFA. Paragraph 47(b) provides that they are subject to the exclusive criminal jurisdiction of their respective participating states for offenses committed in the host country (UN Secretary-General, 1990). Exclusive jurisdiction and immunity are not the same legal concept: the former allocates adjudicative authority to a particular state, while the latter restricts the exercise of otherwise available jurisdiction.
Troop-contributing states carry primary responsibility for investigating alleged criminal misconduct by members of their military contingents. They also retain disciplinary and prosecutorial authority under their national systems. United Nations inquiries may serve administrative or preliminary fact-finding purposes under the applicable arrangements, and cooperation or joint investigative mechanisms may be used, but the Organization does not possess a general criminal jurisdiction over contingent personnel.
The United Nations retains significant administrative powers. Substantiated misconduct may result in repatriation on disciplinary grounds, removal from the mission, or exclusion from future peacekeeping service. These measures are distinct from criminal sanctions, which must be imposed by a competent national or international jurisdiction.
Sexual exploitation and abuse illustrates the importance of maintaining these distinctions. Conduct may violate UN standards and warrant administrative action without constituting an international crime. If it constitutes an offense under national law, investigation and prosecution depend on the jurisdiction of the competent state. Conduct amounting to a war crime, crime against humanity, or another international crime may also engage additional national or international jurisdiction where the required legal conditions are satisfied.
Accountability gaps can emerge when the state possessing exclusive criminal jurisdiction does not investigate or prosecute effectively. That practical failure should not be confused with immunity itself, nor does exclusive jurisdiction make the underlying conduct lawful. Effective accountability depends on the interaction of national criminal jurisdiction, disciplinary mechanisms, institutional measures, and the separate rules governing state and organizational responsibility.
Also read
Conclusion
UN peacekeeping has developed without a single treaty, Charter chapter, or comprehensive legal regime governing every operation. Its authority and legal constraints arise from several interacting sources: the Charter, Security Council decisions, consent where relevant, peacekeeping principles, status arrangements, internal UN instruments, and the bodies of international law applicable to particular actors and conduct.
The layered structure explains why institutional labels cannot resolve difficult legal questions by themselves. A Chapter VII mandate may authorize substantial tactical force without necessarily converting a mission into peace enforcement. Security Council authorization does not displace international humanitarian law once the conditions for its application are satisfied, and the protection afforded to peacekeepers may change when they become participants or parties to hostilities. Immunity, attribution, organizational responsibility, and individual criminal liability likewise answer different questions.
Peacekeeping’s flexibility has allowed the United Nations to develop far beyond the observation and interposition functions of the earliest operations. That development has made legal precision more, rather than less, necessary. Identifying the competent authority, the scope of the mandate, the legal basis for presence and coercion, the rules governing conduct, and the actor responsible for violations is what keeps UN peacekeeping within the international legal order while allowing it to serve as an instrument for the maintenance of international peace and security.
References
Charter of the United Nations (1945) signed 26 June 1945, entered into force 24 October 1945, 1 UNTS XVI.
Convention on the Privileges and Immunities of the United Nations (1946) adopted 13 February 1946, entered into force 17 September 1946, 1 UNTS 15, corrigendum 90 UNTS 327.
Convention on the Safety of United Nations and Associated Personnel (1994) adopted 9 December 1994, entered into force 15 January 1999, 2051 UNTS 363.
Geneva Conventions of 12 August 1949 (1949) adopted 12 August 1949, entered into force 21 October 1950: Geneva Convention I, 75 UNTS 31; Geneva Convention II, 75 UNTS 85; Geneva Convention III, 75 UNTS 135; Geneva Convention IV, 75 UNTS 287.
International Committee of the Red Cross (2025) ‘Commentary on Article 3: Conflicts not of an international character, Geneva Convention IV’ [online]. Available at: ihl-databases.icrc.org/en/ihl-treaties/gciv-1949/article-3/commentary/2025 (Accessed: 1 September 2026).
International Court of Justice (1949) Reparation for Injuries Suffered in the Service of the United Nations, advisory opinion, 11 April 1949, ICJ Reports 1949, p. 174.
International Court of Justice (1962) Certain Expenses of the United Nations (Article 17, paragraph 2, of the Charter), advisory opinion, 20 July 1962, ICJ Reports 1962, p. 151.
International Court of Justice (1971) Legal Consequences for States of the Continued Presence of South Africa in Namibia (South West Africa) notwithstanding Security Council Resolution 276 (1970), advisory opinion, 21 June 1971, ICJ Reports 1971, p. 16.
International Court of Justice (2010) Accordance with International Law of the Unilateral Declaration of Independence in Respect of Kosovo, advisory opinion, 22 July 2010, ICJ Reports 2010, p. 403.
International Criminal Tribunal for the former Yugoslavia (1995) Prosecutor v. Duško Tadić, Decision on the Defence Motion for Interlocutory Appeal on Jurisdiction, Appeals Chamber, Case No. IT-94-1-AR72, 2 October 1995.
International Law Commission (2011) ‘Draft articles on the responsibility of international organizations, with commentaries’, Report of the International Law Commission on the work of its sixty-third session, UN Doc. A/66/10, ch. V, pp. 52–172.
Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts (Protocol I) (1977) adopted 8 June 1977, entered into force 7 December 1978, 1125 UNTS 3.
Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of Non-International Armed Conflicts (Protocol II) (1977) adopted 8 June 1977, entered into force 7 December 1978, 1125 UNTS 609.
Rome Statute of the International Criminal Court (1998) adopted 17 July 1998, entered into force 1 July 2002, 2187 UNTS 3, UN Doc. A/CONF.183/9.
Supreme Court of the Netherlands (2013) State of the Netherlands (Ministry of Defence and Ministry of Foreign Affairs) v. Hasan Nuhanović, judgment, 6 September 2013, Case No. 12/03324, ECLI:NL:HR:2013:BZ9225.
United Nations (2008) United Nations Peacekeeping Operations: Principles and Guidelines. New York: Department of Peacekeeping Operations and Department of Field Support.
United Nations Conduct and Discipline Service (2026a) ‘Disciplinary processes’ [online]. Available at: conduct.unmissions.org/en/disciplinary-processes (Accessed: 2 September 2026).
United Nations Conduct and Discipline Service (2026b) ‘Investigations’ [online]. Available at: conduct.unmissions.org/en/investigations (Accessed: 5 September 2026).
United Nations General Assembly (1956a) Resolution 998 (ES-I), A/RES/998(ES-I), 4 November 1956.
United Nations General Assembly (1956b) Resolution 1000 (ES-I), A/RES/1000(ES-I), 5 November 1956.
United Nations General Assembly (1956c) Resolution 1001 (ES-I), A/RES/1001(ES-I), 7 November 1956.
United Nations General Assembly (2011) Responsibility of international organizations, Resolution 66/100, A/RES/66/100, 9 December 2011.
United Nations Office of Legal Affairs (1993) ‘The right of self-defence of United Nations peacekeeping forces and the exercise of this right—Article 51 of the Charter of the United Nations’, memorandum to the Senior Political Adviser to the Secretary-General, 19 July 1993, United Nations Juridical Yearbook 1993, p. 371.
United Nations Peacekeeping (2026a) ‘Mandates and the legal basis for peacekeeping’ [online]. Available at: peacekeeping.un.org/en/mandates-and-the-legal-basis-for-peacekeeping (Accessed: 2 September 2026).
United Nations Peacekeeping (2026b) ‘Our history’ [online]. Available at: peacekeeping.un.org/en/our-history (Accessed: 3 September 2026).
United Nations Peacekeeping (2026c) ‘Principles of peacekeeping’ [online]. Available at: peacekeeping.un.org/en/node/132275 (Accessed: 3 September 2026).
United Nations Secretary-General (1990) Model Status-of-Forces Agreement for Peace-keeping Operations: Report of the Secretary-General, A/45/594, 9 October 1990.
United Nations Secretary-General (1999) Observance by United Nations Forces of International Humanitarian Law, Secretary-General’s Bulletin, ST/SGB/1999/13, 6 August 1999.
United Nations Secretary-General (2013) Human Rights Due Diligence Policy on United Nations Support to Non-United Nations Security Forces, annex to Identical letters dated 25 February 2013 from the Secretary-General addressed to the President of the General Assembly and to the President of the Security Council, A/67/775–S/2013/110, 5 March 2013.
United Nations Security Council (2013) Resolution 2098 (2013), S/RES/2098 (2013), 28 March 2013.
United Nations Special Committee on Peacekeeping Operations (2008) Report of the Special Committee on Peacekeeping Operations and its Working Group, A/61/19/Rev.1, 9 June 2008, annex II (‘Revised draft model memorandum of understanding’).
