The North Atlantic Treaty Organization (NATO) pact, also known as the North Atlantic Treaty, was ratified on 24 August 1949. This ratification marked the formal establishment of NATO as a collective defense alliance. The treaty was initially signed on 04 April 1949, in Washington, D.C., by 12 founding member countries: Belgium, Canada, Denmark, France, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal, the United Kingdom, and the United States.
The ratification on 24 August 1949, brought the treaty into full effect, committing these nations to the principle of collective defense, where an armed attack against one member is considered an attack against all. This principle, enshrined in Article 5 of the treaty, became the cornerstone of NATO's mission to ensure the security and stability of the North Atlantic region, particularly in the context of the emerging Cold War tensions with the Soviet Union.
NATO's creation was a pivotal moment in post-World War II history, establishing a military and political alliance that would play a crucial role in the geopolitical landscape of the 20th and 21st centuries. Over the decades, NATO has expanded its membership and adapted to new security challenges, but the principles established by the North Atlantic Treaty remain central to its mission.