Agency rulemaking is a dominant form of regulation in the USA. Because of a recently developed electronic interface, it is additionally the most accessible form of political participation. Accordingly, this research explores the nature of electronic political interactions with regulatory agencies. Examining electronic submissions made during rulemaking comment periods, I illustrate how varying degrees of agency and commenter participation impact policy outcomes. Examining three US regulatory agencies, the Federal Aviation Administration (FAA), the Transportation and Security Administration (TSA) and the National Highway Traffic and Safety Administration (NHTSA), reveals that agency participation moderates the impact that electronic comments have on comment period outcomes. Results suggest that electronic participation in the rulemaking process creates a context of dynamic political interaction among commenters and agencies. Moreover, this political context is one where policy outcomes are predicted by the nature and scope of electronic political participation.