during that time, thälmann and the kpd fought the spd as their main political enemy, acting according to the comintern policy which declared social democrats to be "social fascists". by 1927, karl kilbom, the comintern representative to germany, had started to combat this ultra leftist tendency of thälmann within the german communist party, but found it to be impossible when he found stalin was against him. another aspect of this strategy was to attempt to win over the leftist elements of the nazi party, especially the sa, who largely came from a working-class background and supported socialist economic policies. these guidelines on social democracy as "social fascism" remained in force until 1935, when thälmann had been imprisoned. the kpd under thälmann declared that "fighting fascism means fighting the spd just as much as it means fighting hitler and the parties of brüning." thälmann declared in december 1931 that "some nazi trees must not be allowed to overshadow a forest" of social democrats.