North Atlantic Treaty (NATO)

RatifiedMultilateral Treatycollective-defensemilitary-alliancesecurity

Date Adopted

1949-04-04

U.S. Ratification

1949-07-21

Summary

The North Atlantic Treaty established the NATO alliance for collective defense. Article 5 provides that an armed attack against one member shall be considered an attack against all members, triggering collective self-defense. The treaty has served as the cornerstone of Western security architecture since the Cold War and has expanded from 12 original members to 32.

Parties

United StatesUnited KingdomFranceCanadaBelgiumNetherlandsLuxembourgNorwayDenmarkIcelandItalyPortugalGreeceTurkeyGermanySpainPolandCzech RepublicHungaryBulgariaRomaniaEstoniaLatviaLithuaniaSlovakiaSloveniaCroatiaAlbaniaMontenegroNorth MacedoniaFinlandSweden

U.S. Implementing Legislation

Mutual Defense Assistance Act of 1949

Pub. L. 81-329

Authorized military assistance to NATO allies and established the framework for defense cooperation.

NATO Participation Act of 1994

22 U.S.C. § 1928

Facilitated NATO expansion by authorizing transition assistance for prospective members.

Key Cases

Doe v. NATO, No. 1:19-cv-3700 (D.D.C. 2020) — NATO enjoys jurisdictional immunity under the International Organizations Immunities Act