European decision-making on techno-scientific issues has encountered public suspicion and legitimacy problems. These have resulted from government policies promoting specific technologies as if they were objective imperatives. The consequent difficulties have been diagnosed according to various `deficit' models, which in turn inform efforts at governing the societal conflict. Anticipating or responding to European public concerns over agricultural biotechnology (agbiotech) in particular, state bodies have sponsored participatory exercises. Some participants sought to open up technological decisions vis à vis alternative futures and normative choices, but such efforts were marginalised. Questions about agbiotech as control were displaced and channelled into regulatory issues and control measures. Despite aspirations to democratise technological choices, the exercises tended to biotechnologise democracy. To some extent, participatory technology assessment (TA) exercises anticipated, stimulated or reinforced policy changes which enhance the state's accountability for regulatory frameworks—but not for its commitment to a specific innovation trajectory. Pervasive tensions have arisen between discussing a `common' problem (e.g. how to make agbiotech safe or acceptable) versus containing conflicts around how to define the problem. These tensions have taken the form of contested boundaries—between policy versus scientific issues, between social versus technical ones, as well as between lay versus expert roles—thus performing different models of the public. These dynamics can be analysed by linking critical theories of technology, deliberative democracy, performative interactions and neoliberal governance.