Many models have been developed to explain public attitudes toward nuclear energy. Data from France, Sweden, and the United States are used to evaluate these models, and most are either falsified or shown to apply only to limited periods. Public support for the technology is traced across the life cycle of the nuclear controversies, and different dynamics are found to influence opinion in different periods. Political context is the master variable explaining these differences: confidence in experts dominates prepolitical periods; media attention leads to politicization; basic values are key to attitudes in fully politicized periods; issue attention cycles explain depoliticization. Once conflict is over and a clear policy path has been taken, public opinion tends to support that path rather than simply returning to its prepolitical patterns. Sustained, visible controversy over technologies may reflect serious debate over political and social goals rather than irrational fears stirred by the mass media.