Peaceful coexistence () was a theory, developed and applied by the Soviet Union at various points during the Cold War in the context of primarily Marxist–Leninist foreign policy and adopted by Soviet-allied socialist states, according to which the Socialist Bloc could peacefully coexist with the capitalist bloc (i.e., U.S.-allied states). This was in contrast to the antagonistic contradiction principle that socialism and capitalism could never coexist in peace. The Soviet Union applied it to relations between the western world, particularly NATO countries, and nations of the Warsaw Pact. Debates over differing interpretations of peaceful coexistence were one aspect of the Sino-Soviet split in the 1950s and 1960s. During the 1970s, the People's Republic of China under the leadership of its founder, Mao Zedong, argued that a belligerent attitude should be maintained towards capitalist countries, and so initially rejected the peaceful coexistence theory as essentially Marxist revisionism. However, their decision in 1972 to establish a trade relationship with the United States also saw China cautiously adopting a version of the theory to relations between itself and non-socialist countries. From that point through the early 1980s and the adoption of Socialism with Chinese characteristics, China increasingly extended its own peaceful coexistence concept to include all nations. Albanian ruler Enver Hoxha (at one time, China's only true ally) also denounced this and turned against China as a result of the latter's growing ties to the West, as exemplified by Richard Nixon's visit to China in 1972; today, Hoxhaist parties continue to denounce the concept of peaceful coexistence. Peaceful coexistence, in extending itself to all countries and social movements tied to the USSR's interpretation of communism, quickly became modus operandi for many individual communist parties as well, encouraging quite a few, especially those in the developed world, to give up their long-term goal of amassing support for an armed, insurrectionist communist revolution in exchange for more active participation in electoral politics. Soviet policy Khrushchev solidified the concept in Soviet foreign policy in 1956 at the 20th Congress of the Communist Party of the Soviet Union. The policy arose as an attempt to reduce hostility between the two superpowers, particularly in light of the possibility of nuclear war. The Soviet theory of peaceful coexistence asserted that the United States and USSR, and their respective political ideologies, could coexist rather than fighting one another, and Khrushchev tried to demonstrate his commitment to peaceful coexistence by attending