19th-century German philosopher Karl Marx, the founder and primary theorist of Marxism, viewed religion as "the soul of soulless conditions" or the "opium of the people". He believed religion survives because of oppressive social conditions. When this oppressive and exploitative condition is destroyed, religion will become unnecessary, according to Marx. At the same time, he saw religion as a form of working-class protest against poor economic conditions and alienation.Raines, John. 2002. "Introduction". Marx on Religion (Marx, Karl). Philadelphia: Temple University Press. pp. 5–6. Denys Turner, a scholar of Marx and historical theology, classified Marx's views as adhering to post-theism, a philosophical position that regards worshiping deities as an eventually obsolete, but temporarily necessary, stage in humanity's historical spiritual development.D. Turner, "Religion: Illusions and liberation", in: Terrell Carver (ed), The Cambridge Companion to Marx (1991), , p. 337.

In his interpretation and synthesis of Marx, Vladimir Lenin theorized state-sanctioned religion as an ideological apparatus of the bourgeoisie, and its places of worship as institutions providing justification for ruling ideas to the working class, while retaining Marx's view of religion's dual role as proletarian protest and solace. A number of Marxist-Leninist governments in the 20th century, such as the Soviet Union after Vladimir Lenin and the People's Republic of China headed by Mao Zedong, implemented state atheism to allow the "opium" to be decentralized in secular civics, in line with post-theism.

Marxist political theorists and revolutionaries on religion Karl Marx and Friedrich Engels

Karl Marx's religious views have been the subject of much interpretation. In the Critique of Hegel's Philosophy of Right of 1843, Marx said religion is a man-made concept and, as such, reflects human conditions. He saw religion as an "inverted consciousness of the world" reflecting an inverted, unjust society. He argued that religion is both an expression of distress and a protest against the real distress. "Religion is the sigh of the oppressed creature, the heart of a heartless world, and the soul of soulless conditions. It is the opium of the people," Marx wrote. The abolition of religion as "illusory happiness" would lead to real happiness, he said — but only if people were freed from oppressive material conditions.

According to Howard Zinn, "[t]his helps us understand the mass appeal of the religious charlatans of the television screen, as well as the work of Liberation Theology in joining the soulfulness of religion to the energy of revolutionary movements in miserably poor countries". Some recent scholarship has suggested that "opium of the people" is itself a dialectical metaphor, a "protest" and an "expression" of suffering.McKinnon, AM. (2005). 'Reading 'Opium of the People': Expression, Protest and the Dialectics of Religion'. Critical Sociology, vol 31, no. 1–2, pp. 15–38 "Opium as Dialectics of Religion: Metaphor, Expression and Protest".Roland Boer in International Socialism. Issue 123 "The full story: on Marxism and religion".

Some view the early Christian Church, such as the one described in the Acts of the Apostles, as an early form of communism and religious socialism. They believe communism was just Christianity in practice and Jesus was the first communist. This link was highlighted in one of Marx's early writings, in which he wrote: "As Christ is the intermediary unto whom man unburdens all his divinity, all his religious bonds, so the state is the mediator unto which he transfers all his Godlessness, all his human liberty". Furthermore, Thomas Müntzer led a large Anabaptist communist movement during the German Peasants' War which Friedrich Engels analysed in The Peasant War in Germany. The Marxist ethos that aims for unity reflects the Christian universalist teaching that humankind is one and that there is only one God who does not discriminate among people. Tristram Hunt attributes a religious persuasion to Engels.

Roland Boer asserts that Marx's depiction of religion as 'opium', while suspicious of religion's addictive potential, also emphasizes religion's medicinal properties akin to those of opium in Western medicine.

Vladimir Lenin In The Attitude of the Workers’ Party to Religion, Lenin repeated that religion is the "opium of the people" and emphasized that religion and its institutions are instruments of the ruling class.

Nonetheless, Lenin initially allowed Christians and other religious people in the Bolshevik Party. While critical of religion, Lenin also specifically made a point to not include it in Our Programme or his ideological goals, arguing that the religious question is tied to class struggle. He emphasized that religion is a product of capitalism and that unity in the revolutionary struggle "for the creation of a paradise on earth is more important to us than unity of proletarian opinion on paradise in heaven."

In 1919, Lenin partially reversed this stance. Responding to the question of whether people who took part in religious ceremonies could remain in the party, Lenin wrote that he would expel them. Joseph Stalin Joseph Stalin's public statements on religion throughout his years serving as General Secretary of the CPSU were scarce. In 1927, answering the question of an American trade union delegate, Stalin affirmed that the Communist Party must have an anti-religious policy. He said this was because the party stood for science and contrasted the position to the prosecution of Darwinists in America. Stalin also emphasized the importance of undermining the "reactionary clergy who poison the minds of the toiling masses."

Nikolai Bukharin and Evgenii Preobrazhensky In their influential book The ABC of Communism, Nikolai Bukharin and Evgenii Preobrazhensky spoke out strongly against religion, writing that "Communism is incompatible with religious faith". However, the two placed importance on patience, energy, and perseverance toward the religious, saying that forcing atheism on people would set back the movement against religion. "If the church were to be persecuted, it would win sympathy among the masses, for persecution would remind them of the almost forgotten days when there was an association between religion and the defence of national freedom; it would strengthen the antisemitic movement; and in general it would mobilize all the vestiges of an ideology which is already beginning to die out", they wrote.

Anatoly Lunacharsky

God-Building was an idea proposed by some prominent early Marxists of the Bolshevik faction of the Russian Social Democratic Labour Party. Inspired by Ludwig Feuerbach's "religion of humanity", it had some precedent in the French Revolution with the "cult of reason". The idea proposed that in place of the abolition of religion, there should be a meta-religious context in which religions were viewed primarily in terms of the psychological and social effect of ritual, myth and symbolism in an attempt to harness this force for pro-communist aims, both by creating new ritual and symbolism and by re-interpreting existing ritual and symbolism in a socialist context. In contrast to the atheism of Lenin, the God-Builders took an official position of agnosticism.Anatoly Lunacharsky (1908). Religion and Socialism. Moscow. p. 20.

Kim Il-Sung North Korean leader Kim Il Sung wrote about religion in the context of Korea's national liberation struggle against Japan. In that context, Kim criticized the Protestant Christian creed, stating that while "[t]here is no law preventing religious believers from making the revolution," their lack of action led to "non-resistance" and psalms alone could not block the Japanese guns when "decisive battles" were necessary.

Kim's writings addressed the "opium of the people" metaphor twice, both in the context of responding to comrades who object to working with religious groups (Chonbulygo and Chondoism). In the first instance, Kim replies that a person is "mistaken" if he or she believes the proposition that religion is the "opium of the people" can be applied in all instances, explaining that if a religion "prays for dealing out divine punishment to Japan and blessing the Korean nation" then it is a "patriotic religion" and its believers are patriots. In the second, Kim states that Marx's metaphor "must not be construed radically and unilaterally" because Marx was warning against "the temptation of a religious mirage and not opposing believers in general." Because the communist movement in Korea was fighting a struggle for "national salvation" against Japan, Kim writes that anyone with a similar agenda can join the struggle and that "even a religionist ... must be enrolled in our ranks without hesitation."

Religion in Marxist–Leninist states

Soviet Union

The Soviet Union was an atheist stateSabrina Petra Ramet, Ed., Religious Policy in the Soviet Union. Cambridge University Press (1993). p. 4John Anderson, Religion, State and Politics in the Soviet Union and Successor States, Cambridge University Press, 1994, pp 3 in which religion was largely discouraged and at times heavily persecuted."Anti-religious Campaigns". According to various Soviet and Western sources, over one-third of the country's people still professed religious belief (Christianity and Islam had the most believers). Christians belonged to various churches: Orthodox, which had the largest number of followers; Catholic; Oriental Orthodox (mainly Armenian Apostolic Church) and Baptist and other Protestant denominations. The majority of the Islamic faithful were Sunni (with a notable Shia minority, mainly in Azerbaijan), while Judaism also had many followers. Other religions, which were practiced by a relatively small number of believers, included Buddhism and Shamanism. After 1941 in the Stalin era, religious persecution was greatly reduced. To gather support from the masses during World War II, the Stalin government re-opened thousands of temples and extinguished the League of Militant Atheists. Atheist propaganda returned to a lesser extent during the Khrushchev government and continued in a less strict way during the Brezhnev years.

The role of religion in the daily lives of Soviet citizens varied greatly, but two-thirds of the Soviet population were irreligious. About half the people, including members of the ruling Communist Party and high-level government officials, professed atheism. For the majority of Soviet citizens, religion seemed irrelevant. Prior to its collapse in late 1991, official figures on religion in the Soviet Union were not available. State atheism in the Soviet Union was known as gosateizm.Protest for Religious Rights in the USSR: Characteristics and Consequences, David Kowalewski, Russian Review, Vol. 39, No. 4 (Oct., 1980), pp. 426–441, Blackwell Publishing on behalf of The Editors and Board of Trustees of the Russian Review

Socialist People's Republic of Albania