Does oil hinder democracy?

Some scholars suggest that the Middle East's oil wealth helps explain its failure to democratize. This article examines three aspects of this "oil impedes democracy" claim. First, is it true? Does oil have a consistently antidemocratic effect on states, once other factors are accounted for? Second, can this claim be generalized? Is it true only in the Middle East or elsewhere as well? Is it true for other types of mineral wealth and other types of commodity wealth or only for oil? Finally, if oil does have antidemocratic properties, what is the causal mechanism? The author uses pooled time-series cross-national data from 113 states between 1971 and 1997 to show that oil exports are strongly associated with authoritarian rule; that this effect is not limited to the Middle East; and that other types of mineral exports have a similar antidemocratic effect, while other types of commodity exports do not. The author also tests three explanations for this pattern: a "rentier effect," which suggests that resource-rich governments use low tax rates and patronage to dampen democratic pressures; a "repression effect," which holds that resource wealth enables governments to strengthen their internal security forces and hence repress popular movements; and a "modernization effect," which implies that growth that is based on the export of oil and minerals will fail to bring about the social and cultural changes that tend to produce democratic government. He finds at least limited support for all three effects.