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 it is 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 term "Socialist state" is widely used by Marxist-Leninist parties, theorists and governments to mean a state under the control of a vanguard party that is organizing the economic, social and political affairs of said state toward the construction of socialism. States run by Communist parties that adhere to Marxism–Leninism, or some variation thereof, refer to themselves as "Socialist states" or "workers' states". They involve the direction of economic development toward the building up of the productive forces to underpin the establishment of a socialist economy, and usually include that at least the commanding heights of the economy are nationalized and under state ownership. This may or may not include the existence of a socialist economy, depending on the specific terminology adopted and level of development in specific countries. For example, the Leninist definition of a socialist state is a state representing the interests of the working class which presides over a state capitalist economy structured upon state-directed accumulation of capital, with the goal of building up the country's productive forces and promoting worldwide socialist revolution, with the realization of a socialist economy as the long-term goal.
In the Western world, particularly in mass media, journalism and politics, these states and countries are often called "Communist states" (though they do not use this term to refer to themselves), despite the fact that these countries never claimed to have achieved communism in their countries—rather, they claim to be building and working toward the establishment of socialism (and the development towards communism thereafter) in their countries.
Karl Marx and subsequent thinkers in the Marxist tradition conceive of the state as representing the interests of the ruling class, partially out of material necessity for the smooth operation of the modes of production it presides over. Marxists trace the formation of the contemporary form of the sovereign state to the emergence of capitalism as a dominant mode of production, with its organizational precepts and functions designed specifically to manage and regulate the affairs of a capitalist economy. Because this involves governance and laws passed in the interest of the bourgeoisie as a whole and because government officials either come from the bourgeoisie or are dependent upon their interests, Marx characterized the capitalist state as a dictatorship of the bourgeoisie. Extrapolating from this, Marx described a post-revolutionary government on the part of the working class or proletariat as a dictatorship of the proletariat because the economic interests of the proletariat would have to guide state affairs and policy during a transitional state. Alluding further to the establishment of a socialist and communist economy where social ownership displaces private ownership, and thus class distinctions on the basis of private property ownership are eliminated, the modern state would have no function and would gradually "whither away" or be transformed into a new form of governance.
Influenced by the pre-Marxist utopian socialist philosopher Henri de Saint-Simon, Friedrich Engels theorized the nature of the state would change during the transition to socialism. Both Saint-Simon and Engels described a transformation of the state from an entity primarily concerned with political rule over people (via coercion and law creation) to a scientific "administration of things" that would be concerned with directing processes of production in a socialist society, essentially ceasing to be a state.