Public comment periods are a primary mechanism for engaging citizens in Environmental Impact Statement (EIS) processes and, in turn, federal decisions with significant environmental, economic and cultural impacts. Yet citizens often feel disenfranchised throughout the five main stages of these comment periods. As a result, when members of the public participate in public comment periods, they are increasingly doing so not only to provide feedback on a given proposed project but to critique the nature of civic engagement and democratic decision-making occurring today. EIS public comment periods are thus at times transforming from a means of enhancing the sustainability of federal actions to a civic tool for challenging what are viewed to be exclusive governance practices. Improving the dynamics of public involvement in EIS public comment periods by engaging citizens earlier, developing clearer guidelines for incorporating civic input into decision-making, diversifying EIS preparers, and moving public comment periods to a deliberative model can enhance democratic engagement and the environmental, economic and cultural sustainability of future government actions.