In Western usage, the term "communist state" is often used in reference to single-party socialist states governed by parties adhering to a variant of Marxism–Leninism or Maoism, though these states officially refer to themselves as "socialist states" or states that are in the process of building socialism and do not describe themselves as "communist" or as having achieved communism. Aside from the "communist states", a number of other states have described their orientation as "socialist" in their constitutions. A socialist state is to be distinguished from a multi-party liberal democracy governed by a self-described socialist party, where the state is not constitutionally bound to the construction of socialism. In such cases, the political system and machinery of government is not specifically structured to pursue the development of socialism.
The concept of a socialist state is closely related to "state socialism", the political view that a socialist system can be established through the use of state action or government policies. As such, the concept of a socialist state is usually advocated by Leninists and Marxist–Leninists, but rejected as being either unnecessary or counterproductive by some classical Marxists, libertarian socialists and political thinkers who view the modern state as a byproduct of capitalism which would have no function in a socialist system and as a result cannot be used to construct socialism. In the Marxist–Leninist view, a "socialist state" is a state under the control of a vanguard party that is organizing the economic, social and political affairs of the country toward the realization of socialism. The vanguard party presides over a state capitalist economy structured upon state-directed capital accumulation, with the goal of building up the country's productive forces and promoting worldwide socialist revolution, with the eventual long-term goal of building a socialist economy.
The pre-Marxist utopian socialist thinker Henri de Saint-Simon believed that the nature of the state would change under socialism from that of political rule (via coercion) over people to a scientific administration of things and a direction of processes of production. Specifically, the state would become a coordinating entity for production as opposed to a mechanism for political control. According to Friedrich Engels, Saint-Simon foreshadowed the classical Marxist notion of the development of the state in a socialist society.
Karl Marx understood the state to be an instrument of the class rule, dominated by the interests of the ruling class in any mode of production. Although Marx never referred to a "socialist state", he argued that the working class would have to take control of the state apparatus and machinery of government in order to transition out of capitalism and to socialism. This transitional stage would involve working class interests dominating government policy (the "dictatorship of the proletariat") in the same manner that capitalist class interests dominate government policy under capitalism (the "dictatorship of the bourgeoisie"). Engels argued that as socialism developed, the state would change in form and function: under socialism it is not a "government of people, but the administration of things"; and thus would cease to be a state by the traditional definition.
One of the most influential modern visions of a socialist state was based on the Paris Commune, in which the workers and working poor took control of the city of Paris in 1871 in reaction to the Franco-Prussian War. Marx described the Paris Commune as the prototype for a revolutionary government of the future, "the form at last discovered" for the emancipation of the proletariat. Engels noted that "all officials, high or low, were paid only the wages received by other workers... In this way an effective barrier to place-hunting and careerism was set up". Commenting on the nature of the state, Engels continued: "From the outset the Commune was compelled to recognize that the working class, once come to power, could not manage with the old state machine". In order not to be overthrown once having conquered power, Engels argues that the working class "must, on the one hand, do away with all the old repressive machinery previously used against it itself, and, on the other, safeguard itself against its own deputies and officials, by declaring them all, without exception, subject to recall at any moment". Engels argued such a state would be a temporary affair and suggested a new generation brought up in "new and free social conditions" will be able to "throw the entire lumber of the state on the scrap-heap".