Article 5
NATO's collective defense
Article 5 refers to the collective defense clause of the NATO treaty, which states that an attack on one member nation is considered an attack on all.
Invoked only once—after the September 11, 2001 attacks—it obligates allies to respond, though the nature of response remains at each nation's discretion: Would a cyberattack trigger Article 5?
- member statesCountries within a union
- NATOWestern defense organization
- one for allIndividual effort benefits all
- allianceFormal union of parties
- clauseProvision in agreement
Cold War · Warsaw Pact · nuclear umbrella · invoke · solidarity · deterrence · strategic planning · mutual defense · ratification · treaty obligations · provision · treaty · joint operations · boots on the ground · military readiness · military alliance · allied forces · consensus-building
Article 5unilateral action
Article 5war of aggression
Military attack without provocation
preemptive strike · first strike · unprovoked attack · invasion · offensive war
- newspaper articlePublished journalistic piece
- news articlePublished report of events
- genuine articleAuthentic original item
- scholarly articlePeer-reviewed research publication
- magazine articlePublished piece in periodical
- article of faithUnquestioned foundational belief