In the 19th century political thinker Karl Marx predicted that, as capitalism reached its developed stages, the driving force behind it, the bourgeois class (most simply understood as the property-owning class) would become a reactionary force and would exploit the proletariat (laboring classes) more and more. In response to this the proletariat would revolt and establish a system of communal ownership of the means of production. Lenin modified this theory – saying that imperialist capitalism must be broken at its “weakest link” – Tsarist Russia. Even though the Russian Empire did not have a strong and developed proletarian class – most subjects of the Empire were peasants – a strong, conspiratorial Party could seize power in the name of communism. Once a communist regime had seized power, the developed proletariat class of Europe would revolt against the capitalist system and establish communal ownership of the means of production. Particular hope was placed on the massive working class of Germany. In the first years of Soviet power, the Red Army, under Leon Trotsky, tried to export the revolution; it was, however, driven back from Poland. Although in the early 1920s a proletarian revolution was indeed possible in Germany, because of several factors it did not materialize. Nevertheless, until 1927, the USSR actively supported the fomenting of revolution in Europe through the Communist International and through aid to the various Communist Parties active in European states. With the adoption of the Stalinist doctrine of “socialism in one country” (simply put, the USSR would build socialism on its own territory, and this shining example would be taken by the rest of the world as a superior economic system and would thus encourage socialist revolutions in the developed countries of Europe), active support for revolution in Europe gradually slowed and the hopes for a worldwide revolution faded.