The passage of the Lisbon Treaty is an appropriate time to take stock of the growing literature on comparative EU-US studies regarding regulatory regimes. This paper argues that US administrative rulemaking is far more open to democratic and interest-group participation – less agency-centered – than in Europe. This is because of several factors on the US side which have not received adequate attention in the literature; namely, the "notice and comment" process, and the more recent adoption of negotiated rulemaking (which itself somewhat mirrors corporatist approaches but with a larger set of potential participants). The European approach is opening up, however, due to several recent institutional innovations, facilitated by the ability to innovate and carry "best practices" into relatively new regulatory schemes. To what extent these institutional changes mirror other elements of the U.S. example is a key question that motivates this paper, as is the question of how Brussels may be less amenable to corporatist forms of bureaucratic insulation than member state systems traditionally, given the watering-down of specific industry influence.