Citizen suits are filed disproportionately in a small number of states with robust environmental programs. This bias magnifies disparities across states both directly, by ensuring that standards and procedures are followed in favored states, and indirectly, by driving development with significant environmental impacts towards states in which citizen suits are rare and enforcement is less rigorous. This Article takes a broad perspective of citizen suits filed over two presidential administrations, and examines the connections between the structures of statutory regimes and patterns of litigation.