Article 5 of the NATO Treaty

The North Atlantic Treaty, also known as the Washington Treaty, forms the legal basis of the North Atlantic Treaty Organization (NATO) and was signed on April 4, 1949, in Washington, D.C. by 12 founding member states. The treaty was created to promote stability and well-being in the North Atlantic area through the preservation of peace and security, and to provide a collective defense arrangement against an armed attack by the Soviet Union. The treaty's articles, including Article 1, which promotes peaceful resolution of disputes, and Article 3, which emphasizes the importance of self-help and mutual aid, have guided NATO's actions since its inception.learn more on wikipedia