What military alliance was formed to provide collective security among its member nations in the North Atlantic?

The North Atlantic Treaty Organization (NATO) was formed specifically to provide collective security among its member nations in the North Atlantic region. Established in 1949, NATO's primary purpose is to ensure mutual defense in response to an attack against any member. The principle of collective defense is enshrined in Article 5 of the NATO treaty, stating that an attack against one member is considered an attack against all.

NATO was created in the context of the post-World War II geopolitical landscape, particularly to counter the influence of the Soviet Union in Europe. This alliance includes various countries from North America and Europe, emphasizing collaboration and defense readiness.

The United Nations, while a significant organization focused on international cooperation, peacekeeping, and conflict resolution, does not function as a military alliance. The Southeast Asia Treaty Organization (SEATO) was intended to be a collective defense arrangement in Southeast Asia but was not as effective or enduring as NATO. The Warsaw Pact was also a military alliance, but it was formed in response to NATO and included countries aligned with the Soviet Union rather than the North Atlantic region.