Rousseau sees clearly the necessity, if popular consent in government is to be more than a name, of giving it some constitutional means of expression. For Locke's theory of tacit consent, he substitutes an active agreement periodically renewed. He looks back with admiration to the city-states of ancient Greece and, in his own day, reserves his admiration for the Swiss free cities, Berne and, above all, Geneva, his native place. Seeing in the Europe of his day no case in which representative government was working at all democratically, he was unable to conceive that means might be found of giving effect to this active agreement in a nation-state; he therefore held that self-government was impossible except for a city. He wished to break up the nation-states of Europe, and create instead federative leagues of independent city-states. It matters, however, comparatively little, for the appreciation of Rousseau's political theory in general, that he failed to become the theorist of the modern State. By taking the State, which must have, in essentials, everywhere the same basis, at its simplest, he was able, far better than his predecessors, to bring out the real nature of the "social tie," an alternative name which he often uses for the Social Contract. His doctrine I of the underlying principle of political obligation is that of all great modern writers, from Kant to Mr. Bosanquet. This fundamental unity has been obscured only because critics have failed to put the Social Contract theory in its proper place in Rousseau's system.