Why has an apparently persistent opposition to the European constitution emerged in France, a country so often at the forefront of European construction?
There is the waning popularity of the government, which has failed to tackle an unemployment level of 10 per cent and pushed through contentious social reforms. Traditionally in referendums the French people do not really respond to the questions put to them, but say Yes or No to the presidents asking them. This was true for Charles de Gaulle, Georges Pompidou and François Mitterrand, so why should it be any different for Jacques Chirac?
However, the theory of a punishment vote is flawed, given that the main opposition, the Socialist party, backs the constitution. It may be that the No vote is a wholesale rejection of the political class that has pushed forward the European project and is now losing its credibility. But it is more than a simple change of mood towards politics: it has to do with the entire concept of Europe.
For many, a No vote will be an expression of concern about the recent enlargement. The expansion of the European Union from 15 to 25 member states was a decision taken by political leaders alone, without public consultation, and the influx of labour from eastern and central Europe is seen, often irrationally, as a threat. The prospect of an eventual accession by Turkey, with its population of nearly 100m Muslims, has fuelled controversy and fear.
More generally, the French have been consistently taught by their politicians to see the Union as the source of all their country's ills, whether these are the restrictions imposed by the stability pact, Commission rulings on company mergers, the changes imposed on the agricultural sector, outsourcing as a result of globalisation, the privatisation of public services or the overvaluation of the euro and its negative effect on business.
Europe, therefore, is no longer the mobilising concept that animated an entire generation a few decades ago. Peace, freedom, the euro and the free circulation of people are regarded by all, and particularly the younger generation, as an established and irreversible fact and nothing to wonder at. Instead, the Union has become associated with competition and austerity.
Similar concerns are felt throughout "old Europe". In France, they are felt more sharply - perhaps because of the longstanding French political tradition of giving all debates, particularly on liberalism and the role of the state, an intensely ideological flavour.
These debates have divided the French socialist left to a much greater extent than its German and Spanish counterparts. The constitutional treaty is based on the principle of the free circulation of goods, capital and people, which are anathemas to those hostile to liberalism and committed to the defence of the welfare state. This camp is reinforced by the marked presence in France of ideologies influenced by communism and Trotskyism, including the new trends of anti-globalisation (also espoused by many Greens).
On the right, the Gaullist tradition, unique to France, has always been reluctant to construct a liberal Europe, which would dilute sovereignty and French identity. Although Mr Chirac, the political descendant of General de Gaulle, stands at the front line of the Yes campaign, the fear of seeing France's political sovereignty, economic autonomy and cultural influence weakened by an enlarged Europe is felt by many Gaullists. Then there is the extreme right, which identifies itself with the battle against the opening of borders and for the defence of nationalist values.
The French cartel of No camps, coming from different directions but reflecting the same anxieties towards the European project, is an example of the French exception. The strength of militant ideologies contrasts with the more pragmatic politics that prevails in other European countries. It is significant that, in order to reassure opponents of the constitution, Mr Chirac's speeches stress the "French ideas" that inspired the draft treaty and Europe's ability to serve as a rampart against "ultra-liberal" globalisation.
The debate in France has been recently focusing on the consequences of a negative vote and the prospects for a possible Plan B. There is no doubt that a No vote would legally lead to a continuation of the status quo, albeit in a context of deep confusion. But here the Yes and No camps differ. For the No voters, it would be a useful electric shock. For the Yes voters, it would be a disaster because it would bring about a collapse of a 50-year process and weaken France's credibility in Europe.
Mr Chirac has convinced some voters that a No would make France isolated and marginalised. But the outcome is still uncertain and the No camp is regaining its lead. Nobody will ultimately know the real motives of the voters, but the ongoing campaign will have shown the weight of that "French exception", a deeply rooted phenomenon that will not disappear after the referendum.
The writer, author of Les 101 Mots de la Democratie Francaise(Odile Jacob), is professor of government at the Institut d'Etudes Politiques, Paris