This article sets out to chart the evolving institutional structure of
the EU, in the context of theories about forms of state. 'Forms of st
ate' are taken to be conceptually possible expressions of political au
thority organized at the national and transnational levels, here dealt
with as emphases and qualities to be accented rather than phenomena t
o be sorted into categories. The EU is examined in the light of three
stylized state forms-the Westphalian state, the regulatory state and t
he post-modern state. Each of these captures important elements of the
evolution of the EU, and provides support for analysis of its develop
ment as a form of 'international state'. Such an analysis implies atte
ntion not only to forms of state, but also to related concepts such as
government and governance which give leverage on the exploration of '
international state forms'. Conclusions are drawn about the power of t
he three 'metaphors' used, and the relationship to possible empirical
studies.