Organized violence between political communities has shaped borders, technologies, and memories. War is sustained armed conflict between states or organized groups, typically involving regular or irregular military forces and aimed at compelling an opponent to accept certain terms.

Wars range from limited campaigns to total conflicts that mobilize entire societies. Causes include territorial disputes, resource competition, ideological rivalry, and miscalculation. Outcomes redistribute power, destroy and create states, and leave demographic and psychological scars.

Military history examines strategy, operations, and combat experience; wider historical approaches integrate economic mobilization, home fronts, and cultural representation. International law attempts to regulate the conduct of war and the treatment of combatants and civilians. The recurrence of war alongside efforts to restrain it remains a central problem of political history.

• Sustained armed conflict between organized groups
• Ranges from limited to total mobilization
• Reshapes power, borders, and societies
• Studied from military and social perspectives