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.