For months, France has been buzzing with speculation that Dominique Strauss-Kahn, the popular chief of the International Monetary Fund, would quit his job in Washington to take on President Nicolas Sarkozy in next year’s presidential elections.

On Sunday, French politicians and media met news of his arrest in New York for alleged sexual aggression with stunned disbelief and expressions of national humiliation. The incident threw Mr. Strauss-Kahn’s political party, the Socialists, into confusion and set the stage for a new political calculus that could allow the National Front, the far-right party led by its founder’s daughter, Marine Le Pen, to become a more dominant force during the election campaign.

Even as pollsters cautioned against rushing to judgment and as Mr. Strauss-Kahn’s lawyer, Benjamin Brafman, said his client “will plead not guilty,” his would-be rivals were quick to declare his political death.

“He’s definitely discredited,” Ms. Le Pen said Sunday on French television. “The case and the charges mark the end of his campaign for the presidency, and will likely prompt the IMF to ask him to leave his post.”

Bernard Debré, a lawmaker in Mr. Sarkozy’s center-right UMP party, told French television that the arrest was “a humiliation and an affront to the honor of France. Everyone will now say, ‘Look at what the French do.’ " Mr. Strauss-Kahn’s political career, he added, “must be ended — he will be condemned.”

François Bayrou, a centrist politician who ”lost to Mr. Sarkozy in the last race, said he was amazed. “If the accusations turn out to be true — and even if they are proved false — this is a degrading thing” for France, he said.

Leaders of the Socialist party pleaded with the public to withhold judgment until more facts emerged about his arrest in connection with the alleged sexual attack of a maid at a Manhattan hotel Saturday afternoon.

Ségolène Royale, a leading member of the party who also lost to Mr. Sarkozy in France’s last presidential election, called the charges “staggering” but said he was innocent until proven guilty. She cautioned against turning the situation “into a political soap opera.” The Socialist party leader, Martine Aubry, said she was “stupefied” by the news and called for an emergency meeting of party leaders for Monday. 

The head of France’s Christian Democratic party, Christine Boutin, went further, suggesting that amid the atmosphere of France’s presidential campaign, Mr. Strauss-Kahn may have been set up.   “I really believe that somebody set a trap for Dominique Strauss-Kahn to fall into,” she told French television. “That he could be taken in like that seems astounding, so he must have been trapped.”

In any event, Mr. Sarkozy may not benefit, political analysts say. Over 60 percent of French voters do not want the president to run again in next year’s race, recent polls show. Francois Hollande, a former chief of the Socialist party, has been steadily rising in opinion polls, in part because his down-to-earth image contrasts with the more flamboyant Mr. Sarkozy and Mr. Strauss-Kahn, said Stéphàe Rozès, a public opinion expert and president of Cap, a consultancy. 

If Mr. Strauss-Kahn is out of the picture, he said, Mr. Hollande has a chance of making it into a presidential run-off and face not Mr. Sarkozy but Ms. Le Pen, which he believes would be a ticket to the presidency. It would also confirm the steady rise in the popularity ratings of Ms. Le Pen 10 years after her father faced off with Jacques Chirac in the 2002 presidential election. And it could move the National Front from the margins of the political arena to its center at a time when far-right, anti-immigrant and anti-European parties are making gains across Europe.  nytimes