This article proposes and evaluates four hypotheses about US pollution and environmental policy over the last half … century. First, air and water pollution have declined substantially, although greenhouse gas emissions have not. Second …, environmental policy explains a large share of these trends. Third, much of the regulation of air and drinking water pollution has …

evidence that power plants spend less in water pollution abatement if the governor of the state where the plant is located is a … leads to increased pollution. …

calls on the Environmental Protection Agency (“EPA”) to set the acceptable ambient levels of pollution through the national … ambient air quality standards, while leaving it to the states to decide how to obtain those pollution levels. In contrast … states are empowered to define acceptable ambient pollution levels in water bodies within their borders. What are the details …