A socialist state, socialist republic, or socialist country, sometimes referred to as a workers' state or workers' republic, is a sovereign state constitutionally dedicated to the establishment of socialism. The term "communist state" is often used interchangeably in the West specifically when referring to single-party socialist states governed by Marxist–Leninist, or Titoist in case of Yugoslavia political parties, despite these countries being officially socialist states in the process of building socialism. These countries never describe themselves as communist nor as having implemented a communist society.^[2][3][4] Additionally, a number of countries which are not single-party states based on Marxism–Leninism make reference to socialism in their constitutions; in most cases these are constitutional references alluding to the building of a socialist society that have little to no bearing on the structure and development paths of these countries' political and economic systems.

The idea of a socialist state stems from the broader notion of state socialism, the political perspective that the working class needs to use state power and government policy to establish a socialist economic system. The concept of a socialist state is mainly advocated by Leninists and Marxist-Leninists, and most socialist states have been established by political parties adhering to variations of these political ideologies. The concept of a socialist state is considered unnecessary or counterproductive and therefore rejected by some classical Marxists, libertarian socialists and political thinkers who view the modern state as a byproduct of capitalism which would therefore have no function in a socialist system.^[5] Libertarian socialists and socialist anarchists reject the idea that the state can be used to establish a socialist society due to its hierarchical and arguably coercive nature.

Socialist states in the Marxist-Leninist sense are sovereign states under the control of a vanguard party which is organizing the country's economic, political and social development toward the realization of socialism. Economically this involves the development of a state capitalist economy with state-directed capital accumulation with the long-term goal of building up the country's productive forces while simultaneously promoting worldwide socialist revolution.^[6][7]

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 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.^[8][7] 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.^[7]

Because all socialist states operated along Marxist-Leninist principles of governance, the term "Marxist-Leninist state" or "Marxist-Leninist regime" is also used by scholars, particularly when focusing on the political systems of these countries.^[9]

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.^[10][11]

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. The "dictatorship of the proletariat" would represent this transitional state and would involve working class interests dominating government policy 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", thereby ceasing to be a state by the traditional definition.

One of the most influential modern visions of a transitional state representing proletarian interests 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.^[12] 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".^[13] 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". ^[14] 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".

Socialists that embraced reformism, exemplified by Eduard Bernstein, took the view that both socialism and a socialist state will gradually evolve out of political reforms won in the organized socialist political parties and unions: "The socialist movement is everything to me while what people commonly call the goal of Socialism is nothing".^[15] These views are considered a "revision" of Marxist thought.

Following Marx, revolutionary socialists take the view that the working class grows stronger through its battle for reforms (such as in Marx's time the ten-hours bill):

According to the orthodox Marxist conception, these battles eventually reach a point where a revolutionary movement arises. A revolutionary movement is required in the view of Marxists to sweep away the capitalist state and the "dictatorship of the bourgeoisie", which must be abolished and replaced with a "dictatorship of the proletariat" in order to being constructing a socialist society:

In this view, only through revolution can a socialist state be established.

Whereas Karl Marx and Friedrich Engels and classical Marxist thinkers had little to say about the organization of the state in a socialist society, presuming the modern state to be specific to the capitalist mode of production, Vladimir Lenin pioneered the idea of a revolutionary state based on his theory of the revolutionary Vanguard party and organizational principles of democratic centralism. Adapted to the conditions of semi-feudal Russia, Lenin's concept of the "dictatorship of the proletariat" involved a revolutionary vanguard party acting as representatives of the proletariat and its interests. According to Lenin's April Theses, the goal of the revolution and vanguard party is not the introduction of socialism, which could only be established on a worldwide scale, but to bring production and the state under the control of the soviets of workers' deputies. Following the October Revolution in Russia, the Bolsheviks consolidated their power and sought to control and direct the social and economic affairs of the state and broader Russian society in order to safeguard against counterrevolutionary insurrection, foreign invasion and to promote socialist consciousness among the Russian population while simultaneously promoting economic development.^[6]

These ideas were adopted by Lenin in 1917 just prior to the October Revolution in Russia and published in The State and Revolution. With the failure of the worldwide revolution, or at least European revolution, envisaged by Lenin and Leon Trotsky, the Russian Civil War and finally Lenin's death, war measures that were deemed to be temporary, such as forced requisition of food and the lack of democratic control, became permanent and a tool to boost Joseph Stalin's power, leading to the emergence of Marxism–Leninism and Stalinism as well as the notion that socialism can be created and exist in a single state.

Lenin argued that as socialism is replaced by communism, the state would "wither away"^[17] as strong centralized control progressively reduces as local communities gain more empowerment. As he put succinctly, "[s]o long as the state exists there is no freedom. When there is freedom, there will be no state".

Following Joseph Stalin's consolidation of power in the Union of Soviet Socialist Republics and centralization of political power, Leon Trotsky condemned the Soviet government's policies for lacking widespread democratic participation on the part of the population and for suppressing workers' democratic participation in the management of the economy. Because these authoritarian political measures were inconsistent with the organizational precepts of socialism, Trotsky characterized the Soviet Union as a "deformed workers' state" that would not be able to effectively transition to socialism.

Ostensibly socialist states where democracy is lacking, yet the economy is largely in the hands of the state, are termed by orthodox Trotskyist theories as "workers' states" and not Socialist states,^[18] using the terms "degenerated" or "deformed" workers' states.

The political systems of Marxist-Leninist states revolve around the central role of the party which holds ultimate authority. Internally the party practices a form of democracy called democratic centralism.^[19]

The first socialist state was the Russian Socialist Federative Soviet Republic, established in 1917.^[20] In 1922, it merged with the Ukrainian Soviet Socialist Republic, Byelorussian Soviet Socialist Republic, and Transcaucasian Soviet Federal Socialist Republic into a single federal union - the Union of Soviet Socialist Republics (USSR). The Soviet Union proclaimed itself a socialist state and proclaimed its commitment to building a socialist economy in its 1936 Constitution and a subsequent 1977 Constitution. It was governed by the Communist Party of the Soviet Union as a single-party state ostensibly with a democratic centralism organization, with Marxism-Leninism remaining its official guiding ideology until the Soviet Union's dissolution on December 26, 1991. During the 22nd Congress of the Communist Party of the Soviet Union in 1961, Nikita Khrushchev announced the completion of socialist construction and declared the optimistic goal of achieving communism in 20 years. The Eastern Bloc was a political and economic bloc of Soviet-aligned socialist states in Eastern and Central Europe which adhered to Marxism-Leninism, Soviet-style governance and a Soviet-style command economy.

The People's Republic of China was founded on September 24, 1949, and proclaims itself to be a "Socialist state" in its 1982 constitution.

The Democratic People's Republic of Korea (North Korea) used to be a Marxist–Leninist state. In 1972, the country adopted a new Constitution which changed the official state ideology to Juche, which is held to be a distinct Korean re-interpretation of the former ideology.^[21] Similarly in the Lao People's Democratic Republic, direct references to communism are not included in its founding documents even though it gives direct power to the governing ruling party, the Marxist-Leninist Lao People's Revolutionary Party.

The preamble to the Constitution of the Socialist Republic of Vietnam states that Vietnam only entered a transition stage between capitalism and socialism after the country was re-unified under the Communist party in 1976^[22] 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 (and the progress toward a communist society)".^[23]

A number of countries make reference to socialism in their constitutions that are not single-party states embracing Marxism-Leninism and planned economies. In most cases these are constitutional references to the building of a socialist society and political principles that have little to no bearing on the structure and guidance of these country's machinery of government and economic system.

The preamble to the 1976 Constitution of Portugal states that the Portuguese state has as one of its goals opening "the way to socialist society".^[24]

India, Algeria, Congo Brazaville and Sri Lanka have directly used the term "socialist" in their official constitution and name, respectively.

Poland and Hungary directly denounce "Communism" in their founding documents in reference to their past regimes.^[25][26]

In these cases, the intended meaning of "socialism" can vary widely and sometimes the constitutional references to socialism are left over from a previous period in the country's history. In the case of many Middle Eastern states, "socialism" was often used in reference to an Arab socialist/nationalist philosophy adopted by specific regimes, such as that of Gamal Abdel Nasser and that of the various Ba'ath Parties.

Examples of countries directly using the word "socialist" in their names include the Democratic Socialist Republic of Sri Lanka and the Socialist Republic of Vietnam while a number of countries make references to socialism in their constitutions, but not in their names. These include India^[27] and Portugal. In the constitutions of Hungary, Poland and Croatia, direct condemnation is made to the respective, past socialist regimes. The autonomous region of Rojava, which operates under the principles of democratic confederalism, has been described as a socialist state.^[28]

In the post-war period when nationalisation of large industries was relatively widespread, it was not uncommon for commentators to describe some European countries as "Socialist states" seeking to move their countries toward a socialist economy.

In 1956, for example, leading British Labour Party politician and author Anthony Crosland claimed that capitalism had been abolished in Britain, although others—such as Welshman Aneurin Bevan, Minister of Health in the first post-war Labour government—disputed the claim that Britain was a socialist state.^[29][30] For Crosland and others who supported his views, Britain was a socialist state. For Bevan, Britain had a socialist National Health Service which stood in opposition to the hedonism of Britain's capitalist society. He stated:

When the Socialist Party was in power in France in the post-war period, some commentators claimed that France was a socialist country, although as in the rest of Europe the laws of capitalism still operated fully and private enterprises dominated the economy. In the 1980s, the François Mitterrand government aimed to expand dirigism and scheduled to nationalize all banks, but this attempt faced opposition of the European Economic Community. The same is now applied to Nordic countries with the Nordic model.

In France and the United Kingdom during the height of nationalization in the 1960s and 1970s, public ownership never accounted for more than 15–20% of capital formation, which dropped to 8% in the 1980s in the developed non-socialist countries of the world.^[32]

A variety of non-state socialist positions—such as social anarchism, libertarian socialism and council communism—reject the concept of a "Socialist state" altogether, believing that the modern state is a byproduct of capitalism and cannot be used for the establishment of a socialist system. They reason that a "Socialist state" is antithetical to socialism and that socialism will emerge spontaneously from the grassroots level in an evolutionary manner, developing its own unique political and economic institutions for a highly organized stateless society. Anarcho-communists likewise reject the concept of a "Socialist state" for being antithetical to socialism, but they believe that socialism—and thus communism—can only be established through revolution and dissolving the existence of the state.

Within the socialist movement, a number of criticisms are maintained towards the use of the term "Socialist states" in relation to countries such as China and previously of Soviet Union and Eastern and Central European states before what some term the "collapse of Stalinism" in 1989. Democratic socialists, left communists,^[43] anarchists and some Trotskyists^[44] claim that the so-called "Socialist states" or "people's states" actually presided over state capitalist economies and thus cannot be called "socialist".

Other Trotskyists, while agreeing that these states could not be described as socialist, deny that they were state capitalist.^[45] They support Trotsky's analysis of (pre-restoration) Soviet Union as a workers' state that had degenerated into a "monstrous" bureaucratic dictatorship which rested on a largely nationalized industry run according to a plan of production and claimed that the former Stalinist states of Central and Eastern Europe were deformed workers' states based on the same relations of production as the Soviet Union.