Chapter 29 Study GuideIn a secret deal between British Prime Minister Winston Churchill and Soviet leader JosefStalin in May 1944, Greece became part of the British sphere, in return for Romania and Bulgaria being apportioned to the Soviet sphere of responsibility for occupation at war’s end.On July 16, scientists at the “Manhattan Project,” the US effort to develop and atomic weapon, had succeeded in detonating a plutonium test device in New Mexico.The first confrontation between the Soviet Union and the United States occurred in the Balkans. In Yugoslavia, Josip Broz Tito took over the government and provided Greek communists with aid.In 1948, Tito claimed his right to regional communism, against Stalin’s insistence on unity in the Communist Bloc. Tito withdrew his support for the pro-Stalin Greek communists because a surprising majority of the Greek communists opted for Stalin.Truman announced the Marshall Plan of aid to Europe, named after its architect, the secretary of state George C. Marshall.In addition to the political reasons behind Stalin’s injunction, the Marshall Plan’s requirement of free markets and convertible currencies contradicted the communist ideology of a central command economy.Stalin transformed communist governments in Eastern Europe and the Balkans into the Communist Bloc, and integrated their economies with that of the Soviet Union. This was formalized in 1949 as the Council for Mutual Economic Assistance (COMECON).Cold War Superpowers: United States formed a defensive alliance known as the North Atlantic Treaty Organization (NATO) in 1949. In response, the Soviet Union later formedthe Warsaw Pact in 1955 among the states of the Eastern Bloc.The Soviet Union’s response to the United Nations Security Council declaration that South Korea was entitled to U.N. military aid in 1950 was the Soviet boycott.