Class struggle played a central role in the social policies of the USSR and socialist countries, all of which constitutionally outlined the supremacy of the working class in dictating society's development towards communism. Other classes with interests hostile to those of the working class were subjected to repression. This primarily focused on capitalists, including anyone who derived their living from privately owning property or capital assets. In the USSR, which was founded on a class alliance between workers and peasants, a neo-capitalist class emerged by the 1930s as a result of the New Economic Policy introduced after the end of the civil war. Among the peasants, this new class (called Kulaks) accumulated disproportionately large amounts of wealth through merchant trading and small capital practices. Under Joseph Stalin, the government began to crack down on the Kulaks, to which their resistance was met with violent repression in what could arguably considered a second civil war. Kulaks who resisted the socialization of their assets, along with anyone who collaborated with or fought for them, were punished with imprisonment, deportation to Siberia, or even execution. Lev Kopelev, who was personally involved in actions against villagers deprived of food for collaborating with Kulaks explained his motivation: