The history of European political thought from the fall of Napoleon Bonaparte in 1815 to the fall of the Berlin Wall in 1989 presents historians with a daunting task, given the intersecting political events, ideological motivations, and national differences that must be considered. The American political system found its main European theoretician in Alexis de Tocqueville, who in 1835 published Democracy in America. Western Europeans attentively studied political developments in Britain, such as Clement Attlee's Labourism, and in France, such as Charles de Gaulle presidentialism. Berlin emphasized the "continuity of the European intellectual tradition" and studied British political theory from Hobbes to Locke, from Adam Smith to John Stuart Mill. The Italian political scientist Norberto Bobbio has exhorted Europeans to avoid the mythology of historical subjects such as "the proletariat," "the nation," and "the people" and to pursue the goal of solidifying individual liberty and civil rights.