The concept of collective security is best summarized by the statement provided; An attack on one shall be considered an attack on all.. Collective security became a goal following WWII. Following the war, the United States and the nations of Western Europe formed the collective security arrangement NATO (North Atlantic Treaty Organization) as a method of stopping the spread of communism. The collective security arrangement means that even the smallest nation in NATO not fear invasion by communist forces, as to do so would mean a war with all NATO members. The US is a member of several other collective security arrangements such as SEATO (South East Asian Treaty Organization).