Table of Contents
Collective Security and Collective Defence
Introduction
Collective security and collective defence are important concepts in international security. Although the terms are sometimes used interchangeably, they describe different institutional and strategic arrangements.
Collective security is based on the principle that aggression against one member is a concern for the wider international community and that members should cooperate to respond to aggression.
Collective defence is narrower. It normally refers to an agreement among a defined group of states to defend one another against external attack.
The distinction is particularly important for understanding the United Nations, NATO, regional security organizations and international responses to armed aggression.
Collective Security
Collective security is an arrangement in which states agree to cooperate against aggression or serious violations of international peace regardless of which member or state is responsible.
Its underlying principle is often summarized as:
An attack or act of aggression against one is a concern for all.
Unlike a traditional alliance, collective security is theoretically directed against aggression by any actor, including potentially a member of the system.
The United Nations system is the principal modern institutional framework associated with collective security.
Core Principles
Common security refers to the idea that security can be pursued collectively rather than exclusively through individual national military capabilities.
Collective response means that states coordinate diplomatic, economic, legal or military measures in response to threats to peace.
Aggression refers to the use of armed force by one state against another in circumstances contrary to the principles of international law.
Deterrence through collective action occurs when the combined capabilities of multiple states discourage potential aggression.
Collective responsibility refers to the principle that maintaining international peace and security requires coordinated action rather than purely unilateral responses.
United Nations and Collective Security
The United Nations Security Council has primary responsibility within the UN system for maintaining international peace and security.
The Council may determine the existence of a threat to the peace, breach of the peace or act of aggression and may adopt measures under the UN Charter.
Chapter VI concerns peaceful settlement of disputes.
Chapter VII provides a framework for action concerning threats to the peace, breaches of the peace and acts of aggression.
Sanctions may be used as collective measures against states or other actors.
In certain circumstances, the international system may authorize the use of force.
Collective Defence
Collective defence is a security arrangement in which members commit to assist one another when one or more members face external armed attack.
Collective defence is therefore generally associated with a defined group of states.
Military alliance is a formal or informal security relationship in which states coordinate their military capabilities and policies.
Mutual defence commitment is a promise to provide assistance if another member is attacked.
NATO is a major contemporary example of a collective defence organization.
Its members have undertaken commitments concerning collective defence under the North Atlantic Treaty.
Article 5 and Collective Defence
Article 5 of the North Atlantic Treaty establishes the principle of collective defence among NATO members.
The principle is that an armed attack against one or more members in the treaty’s defined geographic scope is considered an attack against them all, with each member undertaking action it deems necessary to assist the attacked ally.
Collective defence does not necessarily mean that every member responds in exactly the same way. The form of assistance can depend on the circumstances and the decisions of individual governments.
Collective Security versus Collective Defence
The distinction can be summarized as follows:
| Feature | Collective Security | Collective Defence |
|---|---|---|
| Main purpose | Prevent or respond to aggression | Defend members against external attack |
| Membership | Potentially broad | Usually limited |
| Threat | Aggression generally | External attack or defined security threat |
| Main logic | Peace through collective enforcement | Security through mutual defence |
| Example | UN collective security framework | NATO collective defence |
| Orientation | System-wide | Alliance-based |
Alliance Politics
Alliance is a formal or informal relationship between states based on common interests, security commitments or strategic cooperation.
Alliance cohesion refers to the ability of members to maintain common policies and commitments.
Burden sharing concerns the distribution of financial, military, logistical and political responsibilities among members.
Free-riding occurs when a state benefits from collective security arrangements while contributing relatively little to their maintenance.
Interoperability refers to the ability of different armed forces or security organizations to operate effectively together.
Challenges to Collective Security
Veto power can affect the ability of the UN Security Council to take collective action.
National interest may influence whether states support collective measures.
Burden-sharing disputes can create disagreements within alliances.
Threat perception may vary significantly among members.
Collective-action problem occurs when states have an incentive to benefit from collective measures without bearing proportional costs.
Credibility problem arises when members doubt whether others will actually fulfil security commitments.
Collective Security and International Law
Collective security is closely connected with the prohibition on the use of force and the principles contained in the UN Charter.
Self-defence is a legally recognized basis for the use of force under specified circumstances.
Collective self-defence refers to assistance provided by one state or group of states to another state exercising its right of self-defence.
The legal and institutional framework governing collective security is therefore different from purely political military alliances.
Key Distinctions
Collective security is a broad system intended to maintain peace by collectively responding to aggression.
Collective defence is a narrower arrangement in which a defined group of members commits to mutual defence.
Alliance is the relationship among states.
Collective action is the coordinated action undertaken by multiple actors.
Self-defence concerns an individual state’s response to armed attack.
Collective self-defence concerns assistance to another state exercising its right of self-defence.
Key Terms at a Glance
Collective security: Joint action to maintain international peace.
Collective defence: Mutual defence among a defined group of states.
Alliance: Security relationship among states.
Mutual defence: Commitment to assist members facing attack.
Collective action: Coordinated action by multiple actors.
Collective self-defence: Joint response to an attack on another state.
Burden sharing: Distribution of collective security costs.
Free-riding: Receiving collective benefits while making limited contributions.
Interoperability: Ability of forces to operate together.
Alliance cohesion: Degree of unity within an alliance.
Related Glossaries
Related topics include 6.1 International Law: Core Concepts, 7.2 UN Security Council and Collective Security, 9.1 International and National Security, 9.4 Deterrence, Compellence and Containment, 10.5 Conflict Prevention, Management and Resolution, and 13.2 NATO and European Security.