The purpose of this article is to take advantage of historical hindsight in bringing into sharper focus similarities and differences among communist regimes in the USSR and Eastern Europe. The framework for this exercise recognizes several dimensions in three interrelated categories: the political formula, the political culture, and the structure, scope, and exercise of public authority. The questions that these categories suggest allow us to compare the Leninist, Stalinist, and post-Stalin regimes in the Soviet Union with the diverse communist regimes that evolved in East Europe in the more recent period. The contrasts established are not merely of historical relevance. They will also permit the student of contemporary Russia and China to engage in meaningful discourse about these countries' prospects.