UN Security Council – Composition, Powers, Functions and Veto

Introduction

The United Nations Security Council (UNSC) is one of the six principal organs of the United Nations and the organ primarily responsible for the maintenance of international peace and security.

Unlike the General Assembly, whose resolutions are generally recommendatory, the Security Council can adopt binding decisions, particularly under Chapter VII of the UN Charter.

Its work includes:

• preventing and responding to threats to international peace;
• peaceful settlement of disputes;
• imposing sanctions;
• authorising collective measures;
• establishing peacekeeping operations;
• authorising the use of force in appropriate circumstances;
• supporting international peace processes.

The Security Council is therefore the central institution of the UN’s collective security system.

Legal Basis

The principal Charter provisions concerning the Security Council are found in Chapters V, VI, VII, VIII and related provisions.

The most important provisions are:

• Article 23 – composition.
• Article 24 – primary responsibility for international peace and security.
• Article 25 – obligation of UN Members to accept and carry out Security Council decisions.
• Article 26 – regulation of armaments.
• Article 27 – voting and veto.
• Article 28 – organisation and meetings.
• Article 29 – subsidiary organs.
• Article 30 – rules of procedure.
• Article 31 – participation of non-Council members.
• Article 32 – participation of States parties to disputes.
• Articles 33–38 – peaceful settlement.
• Articles 39–51 – action with respect to threats to peace, breaches of peace and acts of aggression.
• Articles 52–54 – regional arrangements.

The core provisions to remember are:

Article 24 → Responsibility

Article 25 → Compliance

Article 27 → Voting and veto

Article 39 → Determination

Article 41 → Sanctions

Article 42 → Force

Article 51 → Self-defence

Composition of the Security Council

Under Article 23, the Security Council consists of 15 members.

They are divided into:

Permanent Members

The five permanent members are:

• China;
• France;
• Russian Federation;
• United Kingdom;
• United States.

They are commonly referred to as the P5.

Elected Members

There are 10 non-permanent members, elected by the General Assembly for two-year terms.

They are elected with due regard to:

• contribution to maintenance of international peace and security;
• other purposes of the organisation;
• equitable geographical distribution.

Permanent and Non-Permanent Members

Permanent Members	Elected Members
5 States	10 States
Permanent seats	Two-year terms
China, France, Russia, UK, USA	Elected by General Assembly
Possess veto power	Do not possess veto
No rotation of the seat	Seats rotate

Presidency of the Security Council

The presidency of the Security Council rotates monthly among its members.

The order is based on the English alphabetical order of the names of the Member States.

The President:

• presides over meetings;
• represents the Council procedurally;
• facilitates Council business.

Article 24 – Primary Responsibility

Article 24 is one of the most important provisions concerning the Security Council.

UN Member States confer on the Security Council primary responsibility for the maintenance of international peace and security.

The Council acts on behalf of the Members in carrying out this responsibility.

This does not mean that the General Assembly has no role in peace and security.

Rather:

Security Council → Primary responsibility

General Assembly → Important supplementary and recommendatory role

Article 25 – Binding Decisions

Article 25 provides that UN Members agree to accept and carry out the decisions of the Security Council in accordance with the Charter.

This is a major reason why Security Council decisions can have binding legal consequences.

However, Article 25 must be read together with the Charter.

Not every statement or communication of the Security Council is automatically a binding “decision” under Article 25.

The legal character depends upon:

• the wording;
• context;
• Charter provision relied upon;
• intention of the Council.

Article 27 – Voting System

Article 27 establishes the voting system.

Each member has one vote.

For procedural matters, an affirmative vote of 9 members is required.

For other matters, an affirmative vote of 9 members including the concurring votes of the permanent members is required.

This gives the permanent members the power commonly called the veto.

The Veto

The veto means that a negative vote by a permanent member can prevent adoption of a substantive Security Council resolution requiring the necessary affirmative votes.

The five veto-holding States are:

China + France + Russia + United Kingdom + United States

The veto is one of the most controversial features of the Security Council.

Important Point About Abstention

An abstention by a permanent member does not necessarily constitute a veto.

A substantive resolution can be adopted with nine affirmative votes even if a permanent member abstains, provided the required voting conditions are satisfied.

This distinction is important:

Negative vote by P5 → May block substantive resolution

Abstention by P5 → Does not automatically block resolution

Procedural and Substantive Matters

The distinction between procedural and substantive matters is important because the veto operates differently.

Procedural Matters

Require the necessary affirmative votes without the permanent-member veto operating in the same way.

Substantive Matters

Require nine affirmative votes including the required concurrence of permanent members.

The Council itself determines whether a matter is procedural where that question arises under its rules.

Article 28 – Meetings

The Security Council is organised so that it can function continuously.

Each member must have a representative at the seat of the organisation.

The Council may meet:

• regularly;
• when required;
• at the request of members;
• when circumstances demand urgent action.

Article 29 – Subsidiary Organs

Under Article 29, the Security Council may establish subsidiary organs as necessary for the performance of its functions.

Examples include:

• sanctions committees;
• investigative mechanisms;
• tribunals historically established by the Council;
• working groups;
• committees concerning particular situations.

Article 30 – Rules of Procedure

The Security Council adopts its own rules of procedure.

These govern matters such as:

• meetings;
• agenda;
• voting;
• participation;
• procedural arrangements.

Article 31 – Participation of Non-Members

A UN Member that is not a member of the Security Council may participate, without vote, in discussion of a question before the Council when its interests are specially affected.

Article 32 – States Parties to a Dispute

A State that is not a member of the Security Council and is a party to a dispute under consideration may be invited to participate without vote, subject to the Charter conditions.

Chapter VI – Peaceful Settlement of Disputes

Chapter VI provides the Security Council with functions concerning the peaceful settlement of disputes.

The principal provisions are:

• Article 33 – peaceful means;
• Article 34 – investigation;
• Article 35 – bringing disputes to the Council;
• Article 36 – recommendation of procedures or methods;
• Article 37 – recommendation when parties fail to settle;
• Article 38 – recommendations upon request of all parties.

Article 33 – Peaceful Means

Article 33 identifies peaceful methods including:

• negotiation;
• enquiry;
• mediation;
• conciliation;
• arbitration;
• judicial settlement;
• resort to regional agencies or arrangements.

The parties should seek a peaceful solution where continuation of the dispute is likely to endanger international peace and security.

Article 34 – Investigation

The Security Council may investigate:

• any dispute; or
• any situation

which might lead to international friction or give rise to a dispute.

The purpose is to determine whether continuation of the dispute or situation is likely to endanger international peace and security.

Article 36 – Recommendations

The Security Council may recommend appropriate procedures or methods of adjustment.

It should also take into consideration procedures already adopted by parties for settlement.

Where appropriate, legal disputes should generally be referred to the International Court of Justice.

Article 37

Where parties fail to settle a dispute by peaceful means and continue the dispute in circumstances likely to endanger peace and security, they should refer it to the Security Council.

The Council may recommend terms of settlement or appropriate methods.

Article 38

If all parties to a dispute request it, the Security Council may make recommendations with a view to peaceful settlement.

Chapter VII – Action Concerning Threats to Peace

Chapter VII is the most powerful part of the Security Council’s enforcement framework.

The key provisions are:

Article 39 → Determine situation

↓

Article 40 → Provisional measures

↓

Article 41 → Non-force measures

↓

Article 42 → Force

Article 39 – Determination

Article 39 gives the Security Council authority to determine the existence of:

• any threat to the peace;
• breach of the peace;
• act of aggression.

After making such a determination, the Council may:

• make recommendations; or
• decide what measures shall be taken under Articles 41 and 42.

This determination is the gateway to Chapter VII measures.

Threat to the Peace

The phrase “threat to the peace” is deliberately broad.

The Security Council has developed a wide practice of determining that situations involving:

• armed conflict;
• humanitarian crises;
• terrorism;
• proliferation;
• regional instability

may constitute threats to international peace and security.

The Council enjoys substantial political discretion in making such determinations, subject to the Charter framework.

Article 40 – Provisional Measures

Before making a decision under Articles 41 or 42, the Security Council may call upon parties to comply with provisional measures.

These may be intended to:

• prevent escalation;
• preserve the situation;
• prevent further deterioration.

Examples may include demands for:

• ceasefires;
• withdrawal of forces;
• cessation of hostilities.

Article 41 – Measures Not Involving Armed Force

Article 41 allows the Security Council to decide measures not involving the use of armed force.

Examples include:

• economic sanctions;
• trade restrictions;
• financial restrictions;
• arms embargoes;
• travel bans;
• diplomatic restrictions.

Article 41 provides the legal basis for many UN sanctions regimes.

UN Sanctions

Security Council sanctions may be:

• comprehensive;
• targeted;
• directed at individuals;
• directed at organisations;
• directed at States or particular sectors.

Modern practice has increasingly favoured targeted sanctions.

These may include:

• asset freezes;
• travel bans;
• arms embargoes.

Article 42 – Use of Force

If the measures under Article 41 are inadequate, Article 42 permits the Security Council to take action involving:

• air;
• sea;
• land forces.

Such action may be considered necessary to maintain or restore international peace and security.

This represents the coercive military dimension of the UN collective security system.

Article 43 – Armed Forces Agreements

Article 43 contemplates agreements under which Member States would make armed forces and other assistance available to the Security Council.

However, the Charter’s original model of standing arrangements under Article 43 has not operated in the manner originally envisaged.

The UN does not possess a permanent independent army under Article 43.

Instead, military forces are generally provided by Member States when authorised.

UN Peacekeeping and Security Council

The Security Council plays a central role in establishing or authorising UN peacekeeping operations.

However, peacekeeping is not expressly set out as a separate chapter of the Charter.

It developed through UN practice.

Traditional peacekeeping is associated with:

• consent;
• impartiality;
• limited use of force.

Modern missions may have broader mandates, including civilian protection and robust use of force.

Security Council and Self-Defence

Article 51

Article 51 recognises the inherent right of individual or collective self-defence if an armed attack occurs.

Measures taken in self-defence must be reported to the Security Council.

The right of self-defence exists alongside the collective-security system.

Therefore:

Security Council enforcement

≠

State’s inherent right of self-defence

Collective Self-Defence

Article 51 allows collective self-defence.

A State may assist another State that has suffered an armed attack, subject to the requirements of international law.

The Nicaragua v United States judgment is particularly important concerning the customary-law framework of self-defence and collective self-defence.

Chapter VIII – Regional Arrangements

The Security Council also operates within the framework of Chapter VIII.

Regional organisations can contribute to:

• peaceful settlement;
• maintenance of peace;
• regional security.

Important provisions include:

• Article 52 – regional arrangements;
• Article 53 – enforcement action;
• Article 54 – keeping the Security Council informed.

Article 53

Regional organisations generally cannot undertake enforcement action without Security Council authorisation, subject to the Charter’s specific historical exceptions.

This reflects the central role of the Security Council in the collective-security system.

Security Council and International Court of Justice

The Security Council and ICJ perform different functions.

Security Council

Primarily political and security-oriented.

ICJ

Judicial institution deciding legal disputes between States and giving advisory opinions when properly requested.

The Security Council can request an ICJ advisory opinion under Article 96 of the UN Charter.

Security Council and General Assembly

Security Council	General Assembly
15 members	All UN Member States
Primary responsibility for peace/security	Broad deliberative functions
5 permanent members	No permanent membership
P5 possess veto	No veto
Can adopt binding decisions in appropriate cases	Most substantive resolutions recommendatory
Chapter VII enforcement	No equivalent general Chapter VII enforcement power
Article 24	Article 10 and related provisions

Security Council and Article 103

Article 103 provides that where obligations under the UN Charter conflict with obligations under another international agreement, Charter obligations prevail.

This becomes particularly important in relation to Security Council decisions adopted under the Charter.

The Lockerbie litigation and the Kadi jurisprudence are important for understanding the interaction between Security Council measures and other international/legal obligations.

Security Council and Human Rights

The Security Council is not primarily a human-rights organ, but human-rights concerns can become relevant to international peace and security.

The Council has addressed matters involving:

• genocide;
• mass atrocities;
• protection of civilians;
• terrorism;
• humanitarian crises;
• conflict-related sexual violence.

A situation does not necessarily need to be a traditional interstate war before it can be considered relevant to international peace and security.

Security Council and International Criminal Justice

The Security Council has played a role in international criminal justice.

It established the:

• International Criminal Tribunal for the former Yugoslavia (ICTY);
• International Criminal Tribunal for Rwanda (ICTR).

The Council has also referred situations to the International Criminal Court, most notably:

• Darfur;
• Libya.

This demonstrates the broad institutional consequences of Security Council action.

Security Council and Terrorism

The Security Council has adopted numerous measures concerning international terrorism.

These include:

• sanctions;
• counter-terrorism obligations;
• financing restrictions;
• travel restrictions;
• arms restrictions.

Important Security Council counter-terrorism mechanisms include sanctions committees and specialised bodies.

Security Council and Sanctions Committees

Sanctions regimes are often administered through committees established by the Council.

These committees may:

• oversee implementation;
• consider listings;
• review exemptions;
• monitor compliance;
• maintain sanctions lists.

Binding Force of Security Council Resolutions

Not every Security Council resolution automatically has the same legal effect.

The legal effect depends on:

• whether the Council is acting under a particular Charter power;
• whether the text constitutes a decision;
• the language used;
• the context.

Where the Council adopts a binding decision within its Charter authority, Article 25 requires Members to accept and carry it out.

Judicial Review of Security Council Action

International courts have considered whether and how Security Council measures can be reviewed.

Important jurisprudence includes:

Lockerbie

The Questions of Interpretation and Application of the 1971 Montreal Convention arising from the Aerial Incident at Lockerbie litigation raised important questions about the relationship between treaty obligations and Security Council resolutions.

Kadi

The Kadi litigation before the European courts raised significant questions concerning:

• Security Council sanctions;
• UN obligations;
• fundamental rights;
• review within regional legal orders.

The case is especially important for understanding that the operation of Security Council sanctions can raise constitutional and human-rights questions within domestic or regional legal systems.

Security Council and Jus Cogens

A Security Council resolution does not automatically become lawful merely because it is adopted by the Council.

The relationship between Security Council powers and peremptory norms (jus cogens) remains an important issue in international law.

Article 103 provides priority for conflicting Charter obligations, but it should not simply be treated as a general rule that eliminates all other legal limitations.

Security Council and Article 2(4)

Article 2(4) prohibits States from using or threatening force against:

• territorial integrity;
• political independence;
• or in any other manner inconsistent with the purposes of the UN.

Security Council-authorised enforcement action is part of the Charter’s collective-security framework.

Thus:

Unilateral use of force

must be distinguished from

Security Council-authorised collective action

and

Article 51 self-defence.

Uniting for Peace

The General Assembly’s Resolution 377(V), “Uniting for Peace,” was adopted in 1950.

It developed in response to situations in which the Security Council was unable to act because of disagreement among permanent members.

It provides a mechanism for the General Assembly to consider matters involving threats to peace and security when the Security Council fails to exercise its primary responsibility.

However:

Uniting for Peace does not simply transfer the Security Council’s Chapter VII powers to the General Assembly.

This distinction is important in examinations.

Security Council and Veto Reform

The veto system has been subject to extensive criticism.

Common arguments for reform include:

• expanding permanent membership;
• increasing representation of developing States;
• limiting use of veto in mass-atrocity situations;
• improving geographical representation;
• increasing transparency.

However, changing the composition of the Security Council requires amendment of the UN Charter and therefore faces significant political and legal difficulties.

Limitations of the Security Council

Veto

The veto can prevent collective action.

Political Considerations

Security Council decisions frequently reflect political negotiations among major powers.

Representation

The present permanent membership reflects the post-Second World War international structure rather than contemporary global demographics.

Enforcement Difficulties

Even binding decisions depend significantly on Member-State cooperation.

Selectivity

Critics argue that the Council’s responses can be inconsistent across different crises.

Resource Dependence

The UN depends upon Member States for:

• troops;
• funding;
• intelligence;
• logistical support.

Important Cases

Nicaragua v United States (1986)

Important for:

• prohibition of force;
• self-defence;
• collective self-defence;
• customary international law.

Corfu Channel (1949)

Important for:

• international peace and security;
• State responsibility;
• unilateral action;
• role of international institutions.

Lockerbie Cases

Important for:

• Security Council resolutions;
• treaty obligations;
• Article 103;
• relationship between UN obligations and other international obligations.

Certain Expenses of the United Nations (1962)

Important for:

• powers of UN organs;
• UN expenditure;
• peacekeeping;
• implied powers.

Namibia Advisory Opinion (1971)

Important for:

• Security Council decisions;
• legal effects of UN action;
• obligations of States.

Bosnia Genocide (2007)

Important for:

• genocide;
• State responsibility;
• UN framework;
• prevention.

Security Council Action Flowchart

Situation / Dispute

↓

Security Council Consideration

↓

Article 34 Investigation, if appropriate

↓

Chapter VI Peaceful Settlement

↓

If inadequate / situation threatens peace

↓

Article 39 Determination

↓

Article 40 Provisional Measures

↓

Article 41 Sanctions / Non-Force Measures

↓

If inadequate

↓

Article 42 Military Measures

Collective Security Flowchart

Threat to International Peace

↓

Security Council

↓

Article 39 Determination

↓

Collective Measures

↙︎ ↓ ↘︎

Sanctions
Peacekeeping
Force

↓

Restoration / Maintenance of Peace

Voting Flowchart

Security Council Matter

↓

Procedural?

→ Yes → Required affirmative votes

→ No → 9 affirmative votes + required concurrence of permanent members

↓

P5 Negative Vote

→ Resolution blocked

P5 Abstention

→ Does not automatically block resolution

Quick Revision

• The Security Council is one of the six principal organs of the UN.
• It has 15 members.
• 5 permanent members + 10 elected members.
• P5: China, France, Russia, United Kingdom and United States.
• Non-permanent members serve two-year terms.
• Article 23 → Composition.
• Article 24 → Primary responsibility for international peace and security.
• Article 25 → Members must accept and carry out Security Council decisions in accordance with the Charter.
• Article 27 → Voting and veto.
• Article 29 → Subsidiary organs.
• Chapter VI → Peaceful settlement.
• Article 33 → Peaceful means.
• Article 34 → Investigation.
• Article 36 → Recommendation of procedures/methods.
• Article 37 → Failure of parties to settle.
• Chapter VII → Enforcement framework.
• Article 39 → Threat to peace, breach of peace or aggression.
• Article 40 → Provisional measures.
• Article 41 → Measures not involving armed force, including sanctions.
• Article 42 → Measures involving armed force.
• Article 43 → Armed forces agreements; original system has not operated as envisaged.
• Article 51 → Individual and collective self-defence.
• Chapter VIII → Regional arrangements.
• Security Council can establish or authorise peacekeeping operations.
• Peacekeeping is not expressly established under a separate Charter chapter.
• The veto is available to the five permanent members on substantive matters.
• A permanent member’s abstention is not necessarily a veto.
• Security Council decisions can be legally binding when adopted within its Charter authority.
• Article 103 gives priority to Charter obligations in a genuine conflict with obligations under other international agreements.
• Security Council can establish sanctions regimes.
• It has established international criminal tribunals and referred certain situations to the ICC.
• The General Assembly’s Uniting for Peace mechanism does not simply transfer Chapter VII powers to the Assembly.
• The Security Council’s effectiveness is affected by:
  • veto;
  • political divisions;
  • resource dependence;
  • representation concerns;
  • enforcement difficulties.

One-Line Memory Trick

Articles

23 → Composition

24 → Responsibility

25 → Compliance

27 → Veto

29 → Subsidiary Organs

Chapter VI

33 → Peaceful Means

34 → Investigation

36 → Recommendation

37 → Failure to Settle

38 → Recommendation on Request

Chapter VII

39 → Determine

40 → Provisional Measures

41 → Sanctions

42 → Force

51 → Self-Defence

The easiest sequence is:

39 → Determine

↓

40 → Warn/Preserve

↓

41 → Sanctions

↓

42 → Force

Core Formula

UNSC = 15 Members + P5 Veto + Article 24 + Chapter VI + Chapter VII

Conclusion

The UN Security Council occupies a central position in the UN system because it bears the primary responsibility for the maintenance of international peace and security under Article 24.

Its structure combines five permanent members with veto power and ten elected members, creating a system designed to ensure participation while giving special responsibility to the major powers of the post-Second World War international order.

The Council performs both peaceful-settlement functions under Chapter VI and coercive functions under Chapter VII. Under Article 39 it can determine the existence of a threat to the peace, breach of the peace or act of aggression. It can then adopt provisional measures under Article 40, non-forcible measures such as sanctions under Article 41, and, where necessary, measures involving force under Article 42.

The Council also plays a central role in peacekeeping, sanctions, counter-terrorism, international criminal justice and collective security.

For examinations, the most important sequence is:

Article 24 → Primary Responsibility

Article 25 → Binding Decisions

Article 27 → Voting + Veto

Article 39 → Determination

Article 41 → Sanctions

Article 42 → Force

Article 51 → Self-Defence

The fundamental distinction to remember is:

Security Council = Primary responsibility for international peace and security

while

General Assembly = Broad deliberative and recommendatory organ

and

ICJ = Judicial organ for international legal disputes.