NORTH ATLANTIC TREATY

A treaty signed April 4, 1949, by which the Parties agree that an armed attack against one or more of them in Europe or North America shall be considered an attack against them all; and each of them will assist the attacked by taking forthwith, individually and in concert with the other Parties, such action as it deems necessary, including the use of armed force.

PARTIES: United States, Albania, Belgium, Bulgaria, Canada, Croatia, Czech Republic, Denmark, Estonia, France, Germany, Greece, Hungary, Iceland, Italy, Latvia, Lithuania, Luxembourg, Netherlands, Norway, Poland, Portugal, Romania, Slovak Republic, Slovenia, Spain, Turkey, United Kingdom