This article empirically examines participation in three regulatory rulemaking proceedings, involving financial privacy, nuclear regulation, and campaign finance. It then uses that analysis to critique – and suggest alternatives to – existing mechanisms to achieve public participation in the regulatory state. Under existing law, agencies writing regulatory rules receive input only from those who decide they have sufficient resources and interest to send them – such as organized interest groups or companies facing compliance costs under the new rule. While some consider this demand driven process close to ideal, other observers instead seem to accept the current approach only because it appears to be a reasonable compromise adequate for an imperfect world where legitimate aspirations for widespread public participation meet real world constraints such as limited public attention to complicated regulatory issues. Under this compromise acceptance view, current procedures seem easier to accept in light of certain empirical suppositions, such as that regulatory problems can be resolved through the application of technical, scientific expertise; that individual members of the public tend to lack interest in participating in regulatory policymaking; and that even if they had such interest, they would add little to a process already informed by the views of organized interests. Drawing on an empirical analysis of thousands of public comments on these three regulations as well as a rich empirical literature in political behavior, I question many of these suppositions. (1) Contrary to conventional wisdom, comments from the lay public make up a substantial proportion of total comments about some regulations, showing at least some potential public demand for participation. (2) Dramatic differences exist in the sophistication of comments from interest groups versus individual members of the public, even though laypeople nearly always raise concerns that are relevant to the agency’s legal mandate. (3) Sophistication affects the agency’s acceptance of suggestions in public comments even when controlling for differences in the person or organization making a comment. (4) Interest groups do not always raise the range of concerns raised by comments from the lay public. (5) The larger public’s interest in a particular regulation, and its sophistication to take part in discussing it, are both themselves shaped by the process of how the public is consulted. All this hints at a rich set of possibilities for alternative institutional designs to involve the public in specific regulatory decisions and enhance governance as a whole. I argue that such alternative institutional designs are feasible, and that they would provide regulators with valuable expanded knowledge about how informed members of the public react to regulatory rules. A principled defense of the current approach would therefore rest most plausibly either on an idealized conception of representative politics and interest group politics, or on a sense that no changes to regulatory democracy are politically feasible. Both of those positions need to be defended, and many such defenses are far from satisfying.