The organization formed in 1949 as a collective defense against the Soviet Union is the North Atlantic Treaty Organization (NATO). Established primarily as a military alliance, NATO was designed to provide collective security for its member states against the perceived threat of Soviet expansion in Europe. It fostered collaboration among member countries, ensuring that an attack against one would be considered an attack against all. This framework not only strengthened military cooperation but also played a significant role in shaping the geopolitical landscape of the Cold War, offering a counterbalance to Soviet influence and contributing to the eventual end of the Cold War.