Even before the end of the first world war, during the inter-war years and right up to the outbreak of the second world war, a vein of political thought ran through Europe, which condemned national sovereignties and set up against them the idea of a European federation.

In reality, the federalist trend of thought in the inter-war years remained marginal to the main political currents, and partook more of the nature of prophecy than of politics. In the 1920s and 1930s politics in Europe were both tense and varied, culminating in the emergence of many political-ideological tyrannies. But in spite of the violent divergences over political problems in those years, politics itself, of the right and of the left, of moderates and radicals, of conservatives and revolutionaries, was based on the profound experience which the peoples had lived through during the first world war, namely of the solidity of the nation state. This experience led to the conviction that only on this rock could anything be built.

Just as the revolution of 1848 was preceded by a ‘campaign of banquets’, so, a hundred years later, the European revolution was announced by a ‘campaign of congresses’ spread over the years 1947–1949. These congresses expressed the state of mind, and stimulated the major trends, of a heterogenous and many-sided movement – a movement curiously inefficient in its tactics, and direct in its strategy, but to which the Council of Europe owes its existence, and because of which the Community of the Six has been able to take shape and to win the acceptance of public opinion, and hence of the parliaments and governments responsible to public opinion in those days.

The future historian of European integration is likely to suffer from a surplus of documentation and a shortage of facts. If a certain kind of ignorance, as Lytton Strachey once remarked, is essential to the writing of intelligible history, it has little hope of survival amid the vast accumulation of newspaper cuttings, official statistics, policy speeches, annual reports and statesmen's memoirs with which the present-day scholar must contend. One expert has calculated that ‘the volume of official documents produced by the United Kingdom Government and its agencies during the six war years 1939–45 equalled, in cubic content, the volume of all previous archives of the United Kingdom and of its constituent kingdoms England and Scotland that had survived down to the date of the outbreak of war.’

The Common Market as an issue in domestic British politics under the Macmillan government – and distinct from the negotiations, as such, with the European Economic Community – can be considered under three broad heads. First, there is the question how the decision to seek entry for Britain was taken. How far was it a political decision; how far was it motivated by the views of civil servants; how far was it prompted by interest groups in industry and finance ? Secondly, how did the Conservative Party become converted to the idea of British membership of the European Economic Community and how significant was the opposition to the idea that developed in the party ? The third question is what effect, if any, did domestic political opposition to the Common Market have on the French President's eventual veto of the project ?

Except by implication, the third question is excluded from consideration here. Only a close student of French domestic politics is competent to evaluate how far, if at all, the hostility to the European idea in a section of the Conservative Party and the official objections of the Labour Party to British membership of EEC on any terms that then seemed negotiable, made it easier for the French President to impose his final veto. Conceivably, the possibility that a successor labour government might disown any treaty that the conservatives had signed may have played a marginal part in assisting the President's attitude in the final stages.

We may assume that the present institutional system of the European Communities is only one stage in the long and arduous development of a European constitution. Looked at half a century hence, the trials and errors of the Coal and Steel Community; the abortive projects for a defence community and a political community; the successes and limitations of EEC and Euratom; and the vain search of the six pioneer countries for a formula for political union will appear as the first hesitant but sigruficant steps towards a complete federal system. Limited though the existing Communities are to economic and social affairs, they have now passed a point where their economies are inextricably linked, and where, although progress to more complete political unity is not automatic it is, in the long run, inevitable.

The development of the power of the European Economic Community has given rise to a reaction from those interests which are most directly affected. In order to make sure both that they are informed and that their interests are represented and defended, the various groups concerned have been led to create for themselves new structures at the level of EEC. A parallel relation has thus emerged between the official powers of EEC and the private powers affected by it. These groups, formed on the European level, naturally have neither the solidity nor the effectiveness of professional representation on the national level. Moreover, since such groups are themselves a part of the process of evolution of the political structure, they adapt themselves readily to new political circumstances. But if these European professional organs are not comparable to the national groupings, they cannot be seen as similar to the international associations. They are more numerous – three hundred and fifty to four hundred gravitate towards the European Community. Their action is both more intense and more concrete than that of the international associations, and corresponds to questions with which the community is concerned.

The experience of the European Communities confirms not only that, as the late Otto Kirchheimer put it, ‘opposition is to be found under one form or another in every political community’; but also that a political community is to be found wherever opposition exists in one form or another. The purpose of this study is to investigate the manner in which opposition forces develop in the European Communities to block or to enhance integration.

The setting up of communities, acting through their own powers and with competences of which the national governments have divested themselves by treaty, clearly needs an appropriate institutional framework. The development of the European Communities, their day-today existence raise problems in human relations which are particularly complex and delicate because of the fact that the actual means of coercion: army, police, fiscal and customs authorities, remain in the hands of the national states, accustomed, through centuries of tradition, to enjoy absolute and unrestricted sovereignty.

These difficulties are increased by the addition of novelty : the impossibility of referring to precedent or to well-established practices, as national administrations or traditional diplomacy can do. Thus a new style of relations has had to be invented and applied, which would both help to foster the dialogue indispensable for the mutual understanding of the needs and legitimate aspirations of each of the national partners, and assist in bringing about solutions of common interest and in accordance with the letter and the spirit of the treaty.

Parallel with the efforts which have been made during the last fifteen or twenty years to build, in Churchill's words (1946) ‘a kind of United States of Europe’, much research has been undertaken to try to find out whether public opinion had followed the movement, or perhaps even anticipated it.

I do not intend to recapitulate here in detail all these works, but merely to underline some of the problems which they raise, for the researchers as well as for the men of action and above all for those who, perhaps over-ambitiously, try to reconcile the concerns of the former with those of the latter.