Under a haze of air pollution and growing public activism, Congress passed the Clean Air Act of 1970 (CAA). Congress included in this Act the country’s first environmental citizen suit provision. The provision had the potential to improve significantly the capacity of environmentally concerned citizens and groups to hold polluting industries accountable. The environmental citizen suit provision authorizes any citizen to bring suit against a private defendant for violating the CAA or against the relevant administrative agency for failing to perform a nondiscretionary CAA duty. This provision has served as an important model: every major environmental statute now includes a similar citizen suit provision?