Organized legal professions often play a central role in successful institutional development. The paper’s model examines how legal professions affect institutional reform. Professional review of reform proposals solves a politician’s informational problem in a way that makes democracy, political stability, and professional power substitutes. The model’s applicability is examined by showing that its predictions track the fortunes of lawyers in the USSR and early transition and are consistent with events in 1688 in England and 1789 in France, indicating why these two revolutions had different consequences. The model suggests why and when civil law and common law systems differ.