Proletarian internationalism, sometimes referred to as international socialism, is the perception of all proletarian revolutions as being part of a single global class struggle rather than separate localized events. It is based on the theory that capitalism is a world-system and therefore the working classes of all nations must act in concert if they are to replace it with communism.
Proletarian internationalism was strongly embraced by the first communist party, the Communist League, as exercised through its slogan "Proletarians of all countries, unite!", later popularized as "Workers of the world, unite!" in English literature. This notion was also embraced by the Bolshevik Party. After the formation of the Soviet Union, Marxist proponents of internationalism suggested that country could be used as a "homeland of communism" from which revolution could be spread around the globe. Though world revolution continued to figure prominently in Soviet rhetoric for decades, it no longer superseded domestic concerns on the government's agenda, especially after the ascension of Joseph Stalin. Despite this, the Soviet Union continued to foster international ties with communist and left-wing parties and governments around the world. It played a fundamental role in the establishment of several socialist states in Eastern Europe after World War II and backed the creation of others in Asia, Latin America and Africa. The Soviets also funded dozens of insurgencies being waged against colonialist governments by leftist guerrilla movements worldwide. A few other states later exercised their own commitments to the cause of world revolution. Cuba frequently dispatched internationalist military missions abroad to defend communist interests in Africa and the Caribbean.
Proponents of proletarian internationalism often argued that the objectives of a given revolution should be global rather than local in scope—for example, triggering or perpetuating revolutions elsewhere. Proletarian internationalism is closely linked to goals of world revolution, to be achieved through successive or simultaneous communist revolutions in all nations. According to Marxist theory, successful proletarian internationalism should lead to world communism and eventually stateless communism.
Karl Marx and Friedrich Engels
Proletarian internationalism is summed up in the slogan coined by Karl Marx and Friedrich Engels, "Workers of the world, unite!", the last line of The Communist Manifesto, published in 1848. However, Marx and Engels' approach to the national question was also shaped by tactical considerations in their pursuit of a long-term revolutionary strategy. In 1848, the proletariat was a small minority in all but a handful of countries. Political and economic conditions needed to ripen in order to advance the possibility of proletarian revolution.
For instance, Marx and Engels supported the emergence of an independent and democratic Poland, which at the time was divided between Germany, Russia and Austria-Hungary. Rosa Luxemburg's biographer Peter Nettl writes: "In general, Marx and Engels' conception of the national-geographical rearrangement of Europe was based on four criteria: the development of progress, the creation of large-scale economic units, the weighting of approval and disapproval in accordance with revolutionary possibilities, and their specific enmity to Russia". Russia was seen as the heartland of European reaction at the time.
First International
The trade unionists who formed the International Workingmen's Association (IWA), sometimes called the First International, recognised that the working class was an international class which had to link its struggle on an international scale. By joining together across national borders, the workers would gain greater bargaining power and political influence.
Founded in 1864, the IWA was the first mass movement with a specifically international focus. At its peak, the IWA had 5 million members according to police reports from the various countries in which it had a significant presence. Repression in Europe and internal divisions between the anarchist and Marxist currents led eventually to its dissolution in 1876. Shortly thereafter, the Marxist and revolutionary socialist tendencies continued the internationalist strategy of the IWA through the successor organisation of the Second International, though without the inclusion of the anarchist and anarcho-syndicalist movements.