The conventional wisdom suggests that states with nuclear energy programs are more likely to seek or acquire nuclear weapons. Yet there is a dearth of systematic empirical work that directly assesses this proposition. A systematic analysis of the historical evidence suggests that the link between nuclear energy programs and proliferation is overstated. Although such programs increase the technical capacity of a state to build nuclear weapons, they have important countervailing political effects that limit the odds of proliferation. Specifically, nuclear energy programs increase the likelihood that parallel nuclear weapons programs will be detected and face counterproliferation pressures; they also increase the costliness of nonproliferation sanctions. Contrary to the conventional wisdom, states with nuclear energy programs historically have not been significantly more likely to seek or acquire nuclear weapons. A combination of qualitative and quantitative evidence supports the plausibility of the countervailing political effects of nuclear energy programs.