Introduction

The world was shocked and fascinated by the speed with which Eastern European peoples threw off the yoke of Soviet-imposed governments. Throughout the post-World War II period there were attempts to change the Soviet-imposed system. The USSR resisted such attempts and showed itself willing to intervene militarily. Barrier models emphasize that it is not just the barrier but the interaction of the barrier and the pressures on it that set the scene for rapid change. Because most Soviet and East European experts focused on politics in a “top down” fashion they tended to ignore the popular support for change when change seemed possible (see Kuran 1991 for a model of change focusing on popular attitudes).

One question is why this structure collapsed in 1989: why not in 1968 or 1956? Indeed, taking other outbreaks of popular revolt at random, “why not 1953 or 1970?” One part of the answer clearly lies in Moscow. A change at the center altered the external constraints on popular movements in 1989. Barrier models are necessary condition explanations. Once Moscow had changed, then the possibility of reform could be posed in Eastern Europe. The other part of the answer lies in what opposition movements learned between 1968 and 1989. Gorbachev's reforms did not force reform on East European governments – many of them did not approve of what he was doing in the USSR.