Leaders of France's ruling Socialist party have called on politicians to drop their divisions and compete on a single electoral list in an effort to stop the far-right, anti-immigrant National Front, which registered stunning gains in the first round of the French regional elections on Sunday.
But former French president Nicolas Sarkozy, who leads the centre-right, main opposition Republicans, rejected the idea, thereby raising the possibility that the National Front will do even better in the runoff ballots scheduled for Sunday.
With all the votes counted, the National Front's electoral breakthrough is astonishing. The party has now more than doubled its traditional voter base and is in the lead nationwide, having secured 28 per cent of all the votes cast, ahead of the 27 per cent given to Mr Sarkozy's Republicans and the Socialists' 23 per cent.
The Front, which has never governed a French region, is now favourite to win no fewer than six of France's 13 regions. The outcome is also a personal triumph for party leader Marine Le Pen, who stood and came top with just over 40 per cent of the votes in one of France's most populous northern industrial regions, and for her niece, Ms Marion Marechal-Le Pen, who recorded a similar triumph in a southern region which includes the glamorous beach resorts of the French Riviera.
Claiming that she now heads the "first party of France", Ms Le Pen ascribed her victory to "those who wanted to keep the country authentically French". She struggled to be heard amid the noise of jubilant supporters, who poured onto the streets of cities waving flags and singing the national anthem soon after the results were announced.
The National Front's hard-line stance on Islam and on upholding France's national identity enjoyed a poll boost in the wake of the Paris terrorist attacks three weeks ago. Fears about migrants were evident in the port city of Calais next to the train tunnel which connects France to Britain, home to one of France's largest asylum-seekers' camps locally referred to as "the jungle".
Ms Le Pen said the National Front was "the only party that can reconquer the lost territories of the republic, of Calais, where we won 50 per cent of the votes, or of the suburbs".
What she described as "lost territories" were Calais and the suburbs of major cities, many of which have sizable Muslim populations.
But the rise of the National Front is also a testament to Ms Le Pen's success in transforming the party bequeathed to her by her father from a small group of racists to a mass movement which speaks to real concerns or ordinary people. The party did particularly well in areas of high unemployment, drawing votes mainly from the Socialists.
Last week, Ms Marechal-Le Pen raised a storm in Toulon, a Mediterranean city with a large number of citizens of Arab descent, when she said Muslims could only be French "if they follow customs and a lifestyle that has been shaped by Greek and Roman influence and 16 centuries of Christianity".
"We are not a land of Islam," she said. "In our country... we don't don't wear a veil and we don't impose cathedral-sized mosques."
France's regional authorities have only limited powers. Still, these are large entities with millions of voters each and considerable budgets. Controlling them would give the Front access to spending power and influential local bureaucracies. These are also the last ballots before the presidential election scheduled in 2017. A victory now would certainly boost Ms Le Pen's presidential bid, now regarded as a serious proposition.
In theory, the National Front's electoral tide can still be reversed. Under France's complicated electoral system, regional elections include two rounds, with a party list needing to secure more than 50 per cent of the vote to win outright in the first round, and at least 10 per cent to stand again in the second round, in which the winner is decided by a simple majority.
That means that, although Front candidates now lead in many places, they can still be defeated in the Dec 13 round, provided their opponents unite under one list, which is what the Socialists are trying to persuade the Republicans to do.
But Mr Sarkozy has rejected any electoral deal because he suspects that his Republicans will get the votes of anyone opposing the National Front in the second round without having to make concessions to the Socialists.
He also hopes to eat into the Front's own electorate. Addressing National Front supporters after votes in the first round were counted, he claimed he understood their "worries", but warned that they would "find no solution" in a Front "whose policies would dramatically weaken France" and even bring about "dangerous unrest" to France's ethnically mixed regions.
Mr Sarkozy is a past master at outflanking the Front in second electoral rounds. That is why the National Front has only two seats in the 577-seat Parliament despite regularly polling around 13 per cent of the national vote. Still, a strategy which worked when the Front was struggling to be heard may be risky now,after its electoral breakthrough. Mr Sarkozy will get the verdict on his gamble on Sunday.