THE QUESTION OF THE SIZE AND ESSENTIAL NATURE OF POLITICAL communities, that is to say of areas in which political power is exercised, has often been neglected by writers on politics in favour of an examination of power itself, or of the institutions through which it is exercised. In recent years interest in the topic has been revived by the discussions about ‘integration’ sparked off by the advent of the European Economic Community and other attempts at the creation of supra-national institutions. In the period before the second world war the issue had arisen in a different context, namely in relation to the strains encountered by imperial systems faced with the growing forces of nationalism.