Other historians have argued that nationalism played an especially aggressive, precociously right-wing destructive role during the Second Empire. Ernst Fraenkel, the young Karl Dietrich Bracher, Gerhard A. Ritter, M. Rainer Lepsius, and others identified powerful long-term weaknesses in the Empire's system of government: the blocked development of parliamentarianism, the severely fragmented system of parties that resembled self-contained blocks, and other factors that later burdened Weimar and contributed to its breakdown. Leonard Krieger, Fritz Stern, George Mosse and Kurt Sontheimer emphasized the illiberal, antipluralistic elements in German political culture upon which National Socialist ideas could later build.