The North Atlantic Treaty Organization (NATO) is an intergovernmental military alliance of 32 member states, 30 European and 2 North American. Founded in the aftermath of World War II, the organization implements the North Atlantic Treaty, signed in Washington, D.C., on 4 April 1949. NATO is a collective security system: its independent member states agree to defend each other against attack by third parties.[4] During the Cold War, NATO functioned as a counterweight to the threat posed by the Soviet Union. The alliance remained active after the dissolution of the Soviet Union and the Warsaw Pact, and was involved in military operations in the Balkans, the Middle East, South Asia, and Africa. The organization's motto is "an unfettered mind in deliberation" (in Latin "animus in consulendo liber"). NATO was formed with 12 founding members and has added new members 10 times, most recently when Sweden joined the alliance on 7 March 2024.[5] In addition, NATO recognizes Bosnia and Herzegovina, Georgia, and Ukraine as aspiring members. The expansion has created tensions with Russia, which is not a member but participates in the Partnership for Peace program, along with 18 other countries. Another 19 countries are involved in institutionalized dialogue programs with NATO.