The success of the Bolshevik Revolution confirmed that economic backwardness was not necessarily an obstacle for socialism, as it triggered the radicalization of leftist movements in the region. Yet this also led to polarization of the left on questions of Soviet-Russian developments and possible cooperation with non-socialist parties, as well as agrarian and national questions. While in many countries social democracy entered the political mainstream in the 1920s, its position was undermined by the rise of right-wing authoritarianism. In turn, the Great Depression made the communist position more plausible, but the Stalinization of communist parties and the imposition of socialist realism alienated most intellectual supporters. Eventually, some radical leftists turned against the communist movement attacking its dogmatism and the Stalinist show trials. At the same time, the rise of Nazism forced leftist groups to seek a common ground, first in the form of “Popular Front” ideology, and, during the war, in the form of armed partisan movements.
