This article examines the new institutionalist research agenda in the
context of the European Union (EU). Specifically, it examines the hist
orical institutionalist approach, setting out different aspects of EU
governance that it may be able to capture: systemic change; differenti
ated governance structures across policy subsystems; policy evolution;
and the normative dimension. The article then examines these differen
t aspects, drawing on evidence associated with the Single European Mar
ket programme, launched in 1985.