In the 1950s, when industrialisation seemed to be triumphing and the welfare state was spreading, numerous theorists were prepared to announce that, in a world where rationalisation was extending ever further, the end of ideologies was at hand. Political sociology also ceased to be concerned with the concept of power and the idea of conflict. In a period in which politics was declared to be at an end, it remained a fortiori anachronistic to enquire into the role of the state. Apolitical, developmentalist perspectives, which saw modernisation in evolutionist terms, with the state being nothing more than a function within a system, were only abandoned much later, when a return to the political – to its history, to its diversity within a range of different cultural spaces, to its structuring in terms of types of specific power – was effected. This accounts for the return, in our own period, to the question of the state, which may be regarded as just one of the many forms of constituted political power. If one rejects both the purely philosophical and the purely institutional conceptions of the state, if one also refuses to regard it as simply a subject of international law endowed with attributes of legitimacy, and if, finally, one wishes deliberately to adopt an ideal-typical approach, one can choose, in one's attempts to account for the extreme diversity of existing institutions, to regard as a state every differentiated political power which is differentiated from social, territorial or partisan peripheries, and which is set going by actors associated with functions whose efficacy increases the more this power, with all its claims to universality, is realised.