The transition from communism in Europe and the former Soviet Union has only sometimes led to democracy. Since the crumbling of the Berlin Wall in 1989 and the collapse of the Soviet Union in 1991, twenty-eight mostly new states have abandoned communism. But only eight – the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Slovenia, and just last year, Croatia – have entered the ranks of liberal democracies. The remaining majority of new postcommunist states are various shades of dictatorships or unconsolidated “transitional” regimes.

Why? Why did some states abandon communism for democracy, while others for authoritarian rule? Why are some states stuck in between?

The answers to these questions should be easy for political science. Simultaneous regime change in two dozen countries – all beginning from roughly similar places, but moving along very different trajectories over ten years – provides the perfect parameters to test extant theories and develop new hypotheses about regime change. Clear variation on the dependent variable with a finite set of independent variables offered up a unique laboratory to isolate causal patterns. A decade since the collapse of European communism, however, theory development regarding regime change has advanced only slightly. At the beginning of the decade, Adam Przeworski pointed to the inability to predict communism's collapse as a “dismal failure of political science.” Yet, the paucity of plausible explanations for regime patterns in the postcommunist world ten years later stands as an even greater indictment.