Under what conditions are stable democracies adopted? What facilitates the survival of authoritarian regimes? What determines the occurrence of sudden revolutionary explosions, often leading to expropriation and leftwing dictatorships, such as the Soviet revolution? And, finally, what are the distributional consequences of different political regimes?

To answer these long-standing questions, a large theoretical literature has developed since Aristotle through Marx and Weber. In the last fifty years this body of work has been joined by a vast array of empirical studies in modern political science. Econometric studies have found democracy to be inextricably linked to economic development. In turn, different strands of more historical research have alternatively associated the existence of democratic regimes with either the destruction of the agrarian world, the formation of cross-class coalitions or the growing strength of the working class. Finally, under the renewed influence of neoinstutionalism, several scholars have claimed that a stable democracy can prosper only when sustained by a particular set of constitutional rules and embedded in certain social norms and practices.

Yet for all the extensive treatment that the causes and the consequences of the process of democratization have received, we still lack a convincing theory of political development and transitions. Take, to start with, the well-known positive correlation between democracy and economic development – uncovered by Lipset in 1959, replicated by numerous studies in the following decades, and confirmed by Przeworski and Limongi's sophisticated analysis of the world sample of nations in the period from 1950 to 1990.