War and Armed Conflict

Introduction

War and armed conflict are central concepts in international relations, strategic studies, international law and political history. They describe organized violence involving states, non-state actors or both.

Although the terms are often used interchangeably, they have different analytical and legal applications. War traditionally refers to sustained organized armed violence between political communities, while armed conflict is a broader term commonly used in contemporary international humanitarian law.

Understanding these concepts requires examining their actors, causes, intensity, objectives, methods and legal status.

War

War is organized and sustained armed violence between political communities or organized armed groups for political, strategic or other objectives.

The traditional understanding of war emphasizes the role of states and organized military forces.

Interstate war occurs between two or more states.

Intrastate war occurs primarily within a state.

Civil war is a sustained armed conflict between organized groups within a state, usually involving competition for political control.

Internationalized civil war occurs when external states intervene in an internal armed conflict.

Armed Conflict

Armed conflict is a broader concept that encompasses situations involving organized armed violence meeting relevant factual and legal thresholds.

International humanitarian law generally distinguishes between:

International armed conflict (IAC): Armed conflict involving two or more states.

Non-international armed conflict (NIAC): Sustained armed violence involving a state and organized armed groups, or between organized armed groups, subject to applicable legal criteria.

The distinction determines which provisions of international humanitarian law apply.

Causes of War

Wars can have multiple causes.

Territorial dispute occurs when states or groups contest control over territory.

Resource competition concerns competition over resources such as land, water, minerals or energy.

Security dilemma occurs when defensive measures by one actor are perceived as threatening by another.

Power transition can create tensions when the distribution of capabilities changes significantly.

Nationalism can contribute to conflict when political movements seek territorial control, independence or national unification.

Ideological conflict occurs when opposing political or ideological systems compete for power or influence.

Ethnic conflict involves political or armed competition structured around ethnic identities.

Religious conflict involves disputes in which religious identities or claims play a significant role.

Miscalculation occurs when leaders incorrectly estimate an opponent’s capabilities, intentions or willingness to act.

War Objectives

Political objective refers to the broader political outcome sought through war.

Military objective is a specific objective pursued through military operations.

Limited war is a conflict in which participants restrict their objectives, geographic scope, forces or weapons.

Total war involves extensive mobilization of economic, military and social resources and may involve the entire society.

War of attrition seeks to exhaust an opponent’s military, economic or human resources.

War of annihilation seeks the destruction of an opponent’s organized capacity to resist.

Types of Warfare

Conventional warfare involves established military forces and conventional weapons.

Irregular warfare emphasizes unconventional methods and competition involving state and non-state actors.

Asymmetric warfare occurs when opposing actors possess significantly different capabilities and therefore employ different strategies and methods.

Guerrilla warfare involves irregular forces using mobility, concealment and small-unit tactics against stronger opponents.

Hybrid warfare combines conventional, irregular, cyber, informational, economic and other instruments.

Proxy war involves external powers supporting local actors to pursue strategic objectives indirectly.

Cyber warfare involves hostile activities conducted through cyberspace for strategic or military purposes.

Escalation

Escalation refers to an increase in the intensity or scope of conflict.

Horizontal escalation expands conflict geographically or into additional domains.

Vertical escalation increases the intensity of violence within an existing theatre.

De-escalation involves measures designed to reduce the intensity of confrontation.

Escalation control refers to efforts to prevent conflict from expanding beyond intended limits.

Spillover occurs when violence or instability spreads from one conflict area into neighbouring regions.

Civilian Dimension

Modern armed conflict often has major consequences for civilian populations.

Civilian casualty refers to the death or injury of a civilian during conflict.

Displacement occurs when people are forced or compelled to leave their homes because of conflict or insecurity.

Internally displaced person (IDP) is a person forced to leave their home but who remains within their own country.

Refugee is a person who crosses an international border because of circumstances covered by the applicable refugee protection framework.

Humanitarian crisis is a situation in which large numbers of people face serious threats to life, health, security or basic living conditions.

War and International Law

International law distinguishes between rules governing the use of force and rules governing conduct during armed conflict.

Jus ad bellum concerns the legal rules governing when force may lawfully be used.

Jus in bello concerns the rules governing conduct during armed conflict.

International humanitarian law (IHL) regulates the conduct of hostilities and protects persons affected by armed conflict.

Distinction requires parties to distinguish between civilians and combatants and between civilian objects and military objectives.

Proportionality prohibits attacks expected to cause excessive civilian harm in relation to the anticipated concrete and direct military advantage.

Military necessity concerns the use of force necessary to achieve a legitimate military objective within applicable law.

Termination of War

Ceasefire is an agreement or arrangement to stop fighting, either temporarily or indefinitely.

Armistice is a formal agreement to suspend hostilities.

Peace agreement establishes arrangements intended to end or transform a conflict.

Surrender occurs when a party accepts defeat and ceases organized resistance under specified conditions.

Conflict termination refers to the ending of organized violence.

Conflict resolution seeks to address underlying issues and relationships that sustain conflict.

Peacebuilding seeks to establish conditions that reduce the risk of renewed conflict and support sustainable peace.

Key Distinctions

Key Terms at a Glance

War: Organized armed violence pursued for political or strategic objectives.

Armed conflict: Broader category covering legally defined forms of organized armed violence.

Interstate war: War between states.

Civil war: Organized armed conflict within a state.

International armed conflict: Conflict between states.

Non-international armed conflict: Conflict involving organized armed groups within a state under applicable legal criteria.

Limited war: War with restricted objectives or scope.

Total war: War involving extensive mobilization of society and resources.

Escalation: Increase in conflict intensity or scope.

Ceasefire: Suspension of hostilities.

Peace agreement: Agreement intended to end or transform conflict.

Related Glossaries

Related topics include 6.4 International Humanitarian Law, 9.3 Security Dilemma and Strategic Stability, 9.6 Hybrid Warfare and Grey-Zone Competition, 10.2 Interstate and Intrastate Conflict, 10.5 Conflict Prevention, Management and Resolution, and 10.6 Peacekeeping, Peacemaking and Peacebuilding.