A full six months may remain before French voters go to the polls to elect their next president. But the preliminary skirmishing already affords an absorbing preview of the battles to come, as well as glimpses of a nation that is politically, socially and culturally in a state of flux.

The depth of France's current malaise is reflected in the internecine struggles in the country's two major parties over their choice of presidential candidate. The frontrunners have each attained their lead by flouting the rules of the French political game. They have disdained the party hierarchy, renounced traditional clan allegiance and taken their case directly to the television cameras - and thence the people.

This is not the way French party politics is supposed to be conducted - certainly not before the nominees have been chosen. To be sure, there have been fierce struggles in the past. The battle for the Socialist nomination as François Mitterrand's term at the Elysee drew to an end was bloody in the extreme. But for a candidate to have emerged in both parties, not by slaying a rival or wooing the party rank and file, but by trying to demonstrate superior electability, is something new.

It is no wonder the establishments of both parties are unhappy. Their power has been seriously challenged, if not yet taken away, in the key matter of who would best represent their cause at the next election. It is as though a primary election has already been held without anyone consulting them about it.

As our Paris correspondent reports today, a barely disguised civil war has broken out in President Chirac's party, the UMP, over Nicolas Sarkozy, who serves as Interior Minister in the government. M. Sarkozy has spent the best part of half a year promoting himself to the electorate, and is seen by his enemies and rivals as a dangerous upstart who has been seduced by American and British ("Anglo-Saxon") ideas. Allocated the poisoned chalice of the interior ministry not once, but twice, he has so far emerged relatively unscathed, despite periodic whispering campaigns against him, public dramas in his marriage, and two questionably managed crises on illegal immigration. M. Chirac's favoured candidate, the prime minister, Dominique de Villepin, has never stood for office and lags far behind M. Sarkozy in the polls.

The warfare on the right is mirrored on the left, where Ségolène Royal, partner of the party leader, François Hollande, is proposing an almost Blairite programme against the traditionally leftist sympathies of the Socialist Party hierarchy. If she wins the nomination next month - and her opponents have so far proved less inventive than M. Sarkozy's foes in the UMP - it will be for her perceived electability, not because of any enthusiasm for her policies. It could even be argued Mme Royal and M. Sarkozy have more in common with each other than they have with their parties. For each is intent on updating French politics and reforming the country in a way that party traditionalists regard as unacceptably, and distressingly, un-French. And this is refreshing. We have long argued that the sort of liberalising, free-market reforms both propose in their different ways would help reinvigorate an economy and a society that has stagnated in the 11-year presidency of M. Chirac.

It is premature to look forward to a contest that pits one against the other, with their competing visions of a France brought into the 21st century. There is plenty of time for second thoughts or dirty tricks to derail the ambitions of one or both. But the real test will not be the nominations or even the election. It will be whether the French can be persuaded that change is in their best interests. If not, even a modernising president will be thwarted.