ANTI-COMMUNIST JOINT DEFENSE ORGANIZAIONS NATO – North Atlantic Treaty Organization – Extension of the 1948 Brussels Treaty , signed in 1949 – Belgium, Canada, Denmark, France, Great Britain, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal and the US – 1951 Greece and Turkey added – 1955 SEATO –Southeast Asia Treaty Organization -- Australia, France, Great Britain, New Zealand, Pakistan, the Philippines, Thailand, and after 1954, the USA CENTO – 1955 -- Central Treaty Organization – Pakistan, Iran, Turkey, Iraq, and Great Britain – US as an associate member – Iraq withdrew in 1959 -- Iran and Pakistan withdrew in 1979 and the organization became defunct. Rio Pact – 1947 – All countries of the Western Hemispheres except Nicaragua, Ecuador, and Canada.