Under President Dwight Eisenhower, a rollback strategy was considered against communism in Eastern Europe from 1953 to 1956. Eisenhower agreed to a propaganda campaign to roll back the influence of communism psychologically, but he refused to intervene in the 1956 Hungarian Uprising, mainly for fear that it would cause the Third World War. Since late 1949, when the Soviets had successfully tested an atomic bomb, they had been known to possess nuclear weapons.