A major goal of the environmental movement is to conserve or improve the natural environment, but evidence showing that environmental mobilization produces positive environmental outcomes is mixed. This article addresses a fundamental question about the relative impact of pro-environmental mobilization and the scope of an environmental policy regime on the natural environment. Using panel data at the state level from 1990 through 2007, we explore how environmental protest and environmental policies independently (or jointly) reduce CO2 emissions in U.S. states. We find that the level of emissions in a state declines in states with increases in pro-environmental protest, net of the effects of the range of environmental policies enacted, gasoline taxes, liberal attitudes, reliance on the fossil fuel industry, number of registered lobbyist organizations, gross state product, and population size.
