The struggle between the Soviet bloc countries and the Western countries from 1945–1990. The Soviet Union, the USA, and Britain had been wartime allies against Nazi Germany, but even before Germany was defeated they began to differ about the future of Germany and of Eastern Europe. Wartime summit meetings at Yalta and Potsdam had laid down certain agreements, but as communist governments seized exclusive power in Eastern Europe, and Greece and Turkey were threatened with similar takeovers, the Western Powers became increasingly alarmed. From 1946 onwards popular usage spoke of a ‘Cold War’ (as opposed to an atomic ‘hot war’) between the two sides. The Western allies took steps to defend their position with the formation of the Truman Doctrine (1947) and the Marshall Plan (1947) to bolster the economies of Western Europe. In 1949 NATO was formed as a defence against possible attack. The communist bloc countered with the establishment of the Council for Mutual Aid and Assistance (COMECON, 1949) and the Warsaw Pact (1955). Over the following decades, the Cold War spread to every part of the world, and the USA sought containment of Soviet advances by forming alliances in the Pacific and south-east Asia. There were repeated crises (including the Korean War, the Cuban Missile Crisis, and the Vietnam War), but there were also occasions when tension was reduced as both sides sought détente. The development of a nuclear arms race from the 1950s, only slightly modified by a Nuclear Test-Ban Treaty in 1963 and Strategic Arms Limitation Talks (1969–79), maintained tension at a very high level. Senator Joseph McCarthy capitalized on anti-Russian feeling when alleging a communist plot to take over the US government, which led to a political witch-hunt. Tension intensified in the early 1980s with the installation of US Cruise missiles in Europe and the announcement of the experimental US Strategic Defense Initiative plan to shoot down missiles in mid-flight and receded with an agreement in 1987 for limited arms control. It began to recede in 1985 with a resumption of START talks, followed by the INF Treaty (1987). Soviet forces withdrew from Afghanistan in 1989 and pacification in such troubled areas as Nicaragua and Angola followed. In December 1989 Presidents Bush and Gorbachev, at a summit meeting in Malta, declared the Cold War officially ended. By then the communist regimes of the Warsaw Pact countries were collapsing and NATO began to change its role. NATO invited the former Soviet countries, including Russia, to join a ‘partnership for peace’ (inaugurated in 1994) as a first step towards granting them full NATO membership. In 1997 a Russian-NATO Joint Permanent Council was established to reinforce cooperation. Between 1999 and 2009 12 former communist countries joined NATO.