NATO

The North Atlantic Treaty Organization (NATO) is a military alliance founded in 1949 by twelve Western democracies as a collective defense pact against Soviet expansion. The core principle — Article 5, treating an attack on one member as an attack on all — underpinned Western security throughout the Cold War. After 1991 NATO expanded eastward from 16 to 32 members, incorporating most former Warsaw Pact states. Russia's 2022 invasion of Ukraine revitalized NATO's collective defense mission and prompted record increases in European defense spending.

• Existed: 1949 CE – present
• Type: Entity
• Government: Intergovernmental Military Alliance
• Capital: Brussels