Development of Communist states
During the 20th century, the world's first constitutionally socialist state was in Russia in 1917. In 1922, it joined other former territories of the empire to become the Union of Soviet Socialist Republics (USSR). After World War II, the Soviet Army occupied much of Eastern Europe and thus helped establish Communist states in these countries. Most Communist states in Eastern Europe were allied with the Soviet Union, except for Yugoslavia which declared itself non-aligned. In 1949, after a war against Japanese occupation and a civil war resulting in a Communist victory, the People's Republic of China (PRC) was established. Communist states were also established in Cambodia, Cuba, Laos and Vietnam. A Communist state was established in North Korea, although it later adopted its own ideology called Juche. In 1989, the Communist states in Eastern Europe collapsed under public pressure during a wave of non-violent movements which led to the dissolution of the Soviet Union in 1991. Today, the existing Communist states in the world are in China, Cuba, Laos and Vietnam.
These Communist states often do not claim to have achieved socialism or communism in their countries—rather, they claim to be building and working toward the establishment of socialism in their countries. For example, the preamble to the Socialist Republic of Vietnam's Constitution states that Vietnam only entered a transition stage between capitalism and socialism after the country was re-unified under the Communist Party in 1976 and the 1992 Constitution of the Republic of Cuba states that the role of the Communist Party is to "guide the common effort toward the goals and construction of socialism".