PARIS — French voters resoundingly rejected the proposed European Union constitution Sunday, handing a devastating political defeat to President Jacques Chirac of France and perhaps a fatal blow to the treaty that seeks to pull the 25 member countries together in a closer union.

A bitter, divisive campaign concluded with a high turnout for the referendum, estimated at 70 percent. According to the Interior Ministry, the "no" camp won with 54.9 percent of the vote, while 45.1 percent voted "yes."

The "no" vote was seen by analysts and commentators as a political earthquake that would probably transform the landscape of French politics and cause wider repercussions across Europe, where discontent is breaking out over stagnant economies and a political elite perceived as out of touch with the demands of voters.

Nine European countries, including Germany, have approved the constitution, but opinion polls indicate that the Netherlands will join France in rejecting the treaty in a vote set for Wednesday.

The "no" vote in France, one of the founding members of the European Union and the principal architect of the constitution, in effect kills the proposed treaty — at least in its current form — because it requires unanimous approval by the 25 countries.

In a short address on national television shortly after the polls closed, Chirac, who had campaigned hard for a "yes" vote, said he accepted the voters' "sovereign decision," but conceded it created "a difficult context for the defense of our interests in Europe."

Chirac added he would make a decision on the future of his center-right government in the coming days, hinting at a possible government shake-up.

After the vote, there were calls among some of the most extreme opponents of the constitution for Chirac to resign.

"We are tonight before a major political crisis," said Philippe de Villiers, head of the right-wing Movement for France and a vocal lobbyist against the constitution. He added that Chirac had two choices: resignation "given the fact that he had been so personally involved," or the dissolution of parliament.

At EU headquarters in Brussels, Prime Minister Jean-Claude Juncker of Luxembourg, the EU president, said the constitution's ratification process must continue.

"The ratification procedure must be pursued in other countries," Juncker said at a news conference. "The European process does not come to a halt today." He said EU leaders would review the situation at their next regular summit on June 16 and 17.

There is a slight chance for the constitution to survive. An EU provision states that if by October 2006 at least one nation has "encountered difficulties" getting the constitution accepted, then a summit will be held to decide how best to proceed.

Dominique Moisi, senior adviser at the French Institute of International Relations, based in Paris, said, "If the Dutch say 'no' decisively, it will be difficult to see any way the treaty will survive."

He said the EU will fall back on existing treaties that hold together the newly enlarged bloc of countries representing 450 million people.

The constitution was intended to formally consolidate those existing treaties, to coordinate legal systems and security policies, and to provide the EU a president and foreign minister so that it could more authoritatively speak with one voice in world affairs.

Daniel Keohane, senior research fellow at the Center for European Reform, an independent think tank based in London, said of the referendum results: "It's a knockout blow for Chirac, but I would say it is only a black eye for the European Union. Life will go on."

There are several possible paths forward, Keohane said, including another vote in the countries that reject the document or a new vote in all 25 countries on a scaled-down version of the 300-page constitution referred to as "treaty-lite."

The Bush administration had publicly expressed its hope that the treaty would pass, since a more unified Europe is seen as a key to repairing the trans-Atlantic alliance, which was frayed by the war in Iraq.

But the foreign policy issue that could be most immediately affected by Sunday's vote is the ongoing effort, led by Europe, to force Iran to bring its nuclear program into compliance with international agreements.

"Iranians now know the EU is weak, and that's a problem," said Keohane.

Analysts said it was a grave miscalculation by Chirac to hold the referendum. Under French law, the treaty could have been approved by parliament and almost certainly would have sailed through.

But Chirac fatefully chose to put it to a referendum, confident that French voters would see the document's merits. Instead, it bitterly divided the country.

Opinion polls before the vote had indicated the French would reject the constitution by a slim margin. But in the end, a large number of undecided voters seemed to go solidly against the constitution.

Marie Deleal, 48, a portrait photographer who emerged from a polling station at an elementary school in the Paris neighborhood of St. Germain des Pres, said: "Until the last moment, I could not decide. But I decided to vote 'no.'

"It's not that I am against Europe," she added. "I am not. But I don't like the Europe we are building. It is getting too big and diluting our culture. I feel like a 'yes' vote is good for the big companies, which will benefit, but not for our culture, which is what I care about. I try to vote with my head on most issues, but this time my gut told me 'no.' "

Michel Robic, 60, a manager of a school for continuing education, said he voted "yes" without hesitation.

"I didn't read a word of the document. It's too complicated, but I know that France must be with Europe. Those who are voting 'no' are doing so to punish the government, but that is ridiculous, and it is something in our character to have to say 'non' to everything.

"But while we are in a corner saying 'non,' the Americans and the Chinese and India are all going to be working and moving ahead, and we'll just keep saying, 'non, non, non.' "

Contributing: Elaine Sciolino, New York Times News Service