The effect of gubernatorial political parties on monitoring and enforcement of federal environmental regulation: evidence from the Clean Water Act

According to the U.S. Environmental Protection Agency, states should inspect each of their major water polluters at least once a year. However, studies have shown that the frequency and stringency of inspections depend on factors such as state budgets, state employee costs, and Congressional voting patterns and committee memberships. This paper adds to this literature by examining the effect of gubernatorial political party affiliation on Clean Water Act monitoring and enforcement. Using a regression discontinuity design approach, we find evidence that states with Democratic governors inspect a smaller percentage of their major water polluters, and that they inspect less stringently, compared to states with Republican governors; enforcement actions, however, are similar across states. We find no evidence that these differences in inspections lead to differences in compliance, suggesting that Democratic and Republican governors use different methods to generate compliance with the Clean Water Act.