Dutch voters rejected the proposed constitution for the European Union by a ratio of almost 2 to 1 Wednesday, a grave if predicted new setback for a campaign to grant broad, expanded powers to the 25-nation bloc that has grown to rival the United States in economic and political influence.

Jubilant opponents traded cheers and kisses as their 62 percent to 38 percent victory was announced on television Wednesday night, three days after French voters turned down the 200-plus-page document in a similar protest against the burgeoning size and cost of the union and their national government's domestic policies.

The two defeats left European leaders scrambling for ways to salvage the constitution. It was written in hopes of streamlining decision-making and giving the Brussels-based organization new say on issues as diverse as a common foreign policy and rules for buying vacation homes on the Mediterranean island of Malta.

Each member country must approve the constitution if it is to take effect by late 2006. Unless the French and the Dutch decide to vote again and wind up reversing themselves -- events that seem unlikely given wide voting margins against the document -- it will not survive in its present form. Still, European leaders said they would press to continue the ratification process in hopes that the rest of the continent will line up in favor.

"Of course, I'm very disappointed," said Prime Minister Jan Peter Balkenende, who, like most elected leaders in the Netherlands, campaigned for the measure. Appearing on television to concede defeat shortly after the polls closed at 9 p.m., he promised to respect the results of the nonbinding vote and said he would not allow parliament to override it.

"The Dutch people have spoken," he said. "I will be telling my foreign colleagues that the Dutch 'no' must be heeded."

The national referendum was the first in Dutch history and drew a higher-than-predicted turnout of about 60 percent.

Like the French, many Dutch voters said in interviews that they were concerned the E.U. had grown too fast in recent years. They opposed giving more power to bureaucrats in Brussels to regulate everyday life across the continent. Others characterized their displeasure as a protest vote against the Dutch government, which has been hobbled in opinion polls by a weak economy and unpopular immigration policies.

"Europe is big now, and that's a good thing," said Peer van der Wonde, a 52-year-old artist and furniture designer, after he voted no at city hall in The Hague, the Netherlands' seat of government. "But we have to be careful. In the last 10 years, the people in Brussels have tried to minimize the input of regular people in democratic decisions."

Opposition leaders said they were angry that European officials still had not abandoned the constitution project. Geert Wilders, founder of an anti-immigration party bearing his name, called Balkenende "a sore loser" on Dutch television for insisting that other European countries be given the opportunity to vote on a charter that Wilders characterized as doomed.

"The prime minister has to go to Brussels and say, 'We do not agree with this,' " Wilders said. "The fact that he doesn't dare to say so is very sad. That's the reason why people are completely sick of politics."

Anticipating a Dutch rejection, European leaders said this week that they would decide their next move at a previously scheduled summit from June 16-17 in Brussels.

But officials in Brussels said they were not ready to ditch the constitution. "We want the other member states to have the opportunity to tackle the same debate," said Luxembourg's prime minister, Jean-Claude Juncker, whose government holds the rotating presidency of the European Union.

Leaders in other countries that have yet to vote have sent signals that they are queasy about continuing with the process, worried that the anti-constitution fever could spread to their nations and cause political backlash. In Britain, where skepticism over E.U. policies is firmly entrenched, the government of Prime Minister Tony Blair has hedged on pledges to hold a referendum next year.

The results in France and the Netherlands have been striking because half a century ago both countries were among the six founding members of the European Coal and Steel Community, which evolved into the European Union. They have generally led the way for a stronger, more powerful European presence in world affairs and the global economy, with national governments ceding functions to European institutions.

Nine countries have approved the constitution, but in each case the document was ratified by lawmakers. In two out of three national referenda, voters said no.

"What is happening is a kind of protest of the voters of the Daddy-knows-best model of democracy, which is the paternalistic approach of Dutch political leaders," Hans Wansink, an editorial writer at the newspaper de Volkskrant, said in a telephone interview. "There is a feeling among Dutch voters that they are not considered as adults."

There is also extensive anxiety among the E.U.'s original members about the rapid pace of expansion. Last year, the union took in 10 members, most of them poor, post-communist countries in Eastern Europe; it is set to absorb Romania and Bulgaria in 2007.

A recent decision by the E.U. to begin membership talks with Turkey, a large and predominantly Muslim country, has also provoked a backlash, especially in smaller nations such as the Netherlands that fear their voices will be drowned out.

"I'm not against a united Europe, but I think it's growing too fast," said Vanja van der Leeden, 29, a restaurant worker in The Hague. "At the end of the day, we are always going to have a lesser voice in such a big community, and I'm not sure that's a good thing."

Some citizens appear to have seen a no vote as a protest against immigration policies by which the Netherlands has acquired a Muslim population of at least 10 percent. Tensions flared last November when Dutch filmmaker Theo van Gogh was shot dead in Amsterdam; a Moroccan man who grew up in the Netherlands is awaiting trial on murder charges.

Dutch voters vented their frustration over a number of other concerns. Widespread feelings persist that the Netherlands suffered economically when it traded in the guilder for the euro, the currency now used in 12 countries in Europe.

Another widespread complaint is the cost in tax revenue and subsidies sent to Brussels. The Netherlands sends out more money than it receives.

"We pay too much," said Finance Minister Gerrit Zalm, commenting on television after the vote.

Many politicians here argued to voters that they would ultimately reap great benefits by participating in a stronger European Union. Still, supporters of the constitution said they got a clear message from the Dutch public that it was unhappy about the direction Europe was taking.

"I heard people say they were sitting on a speeding train, and for the first time, they had a chance to jump off. So they did," said Wouter Bos, leader of the Dutch Labor Party. "They had no idea where the train was heading."

Members of the Dutch Socialist Party in Amsterdam cheer at the Netherlands' rejection of the proposed European Union constitution. The outcome followed a rejection in France and left E.U. leaders scrambling to salvage the charter.