Politicians would be outmanoeuvred partly by bewildering them with complexity. An early battle was over the application of "qualified majority voting (QMV)". Two well-recognised ways of reaching a decision are majority voting and unanimity, both of which are simple arrangements that appeal to common sense — QMV is neither. Right from the start in 1958, the QMV system was used in the EU's highest decision-taking body, the Council of Ministers. Each nation had a certain number of votes, and decisions would be reached if a sufficient number of votes had been cast in favour. QMV formulas changed over the years with successive treaties of European integration. The extension of QMV voting (to more interesting subjects than the price of butter and fishing quotas) was to occur slowly and unobtrusively, as the EU acquired more competences. 

Nevertheless, in the 1960s several French politicians were suspicious. The tensions came to the surface in 1965 and 1966, in the celebrated Empty Chair Crisis. The German Walter Hallstein, the Commission's first president, insisted that the Treaty of Rome meant what it said. Decisions about the common agricultural policy could be taken by QMV even if a powerful member state was opposed. France could therefore be outvoted; it did not have a veto. De Gaulle was angry and hostile. Whatever the wording of the Treaty, he believed that France ought to retain a veto. In July 1965 France boycotted the EEC institutions and left empty its chair in the Council of Ministers. Life returned to normal only in January 1966, when the Luxembourg Compromise recognised a member state's ability to exercise the veto where a fundamental national interest was at stake. This ended the squabble, while leaving key issues unresolved.

De Gaulle's defence of unanimity reflected a very different view of European integration from Monnet's supra-nationalism. Although de Gaulle himself never used the phrase, several of his associates proposed the idea of "l'Europe des patries". In this conception nation states agreed matters of common interest at an inter-governmental level, but with national sovereignty preserved. The main attribute of sovereignty was the ability to veto EU decisions. The Council of Ministers could still reach decisions that bound every member state, but it could do so only by unanimity. Where the legislature and government of one of the nations was against a Directive or Regulation, they could say "no" and stop it.

The Monnet and Gaullist conceptions of European integration are not just distinct, but in conflict. In the Monnet version the European Commission is in the driving seat, because in practice it puts up proposals to the Council only after checking that most governments — the governments that constitute a QMV — can agree to them. So the Commission gets its way. By contrast, in a Gaullist structure national parliaments remain in ultimate control.

Deep constitutional issues are raised by the contrast between an inter-governmental union and a federal union on the US model. It is worth emphasising that, in one key respect, the United States of America is far more unified than our own nation. The American Civil War, and decisions reached in court cases afterwards, established the principle that no state could leave the Union. As a result the US is more cemented together than the UK, even though the UK is usually characterised as one of the world's most "unitary" states and the US as a federation. (With Scotland debating its own independence, it is obvious that the UK — a nation without a written constitution — is more flexible and pragmatic about this subject. Could the Shetlands withdraw from an independent Scotland? Could a county leave England?)