MADRID, Feb. 20 -- Spaniards gave an overwhelming "yes" to the European Union's new constitution in a referendum Sunday, but a low turnout may have dented E.U. hopes that the vote would send a strong signal across the 25-nation bloc.
Supporters of the charter had hoped that Spain, the first member state to submit the constitution to a referendum, would set a strong example for waverers in the bloc. But the results showed a mixed picture.
Voters approved the constitution by about 77 percent to 17 percent, official results showed with 83 percent of the votes counted. About 6 percent of votes cast were blank. But turnout was 42.4 percent, short of the already low 45.9 percent turnout in elections for the European Parliament in June.
The opposition Popular Party said turnout was the second lowest among 29 referendums held in the European Union and blamed Prime Minister Jose Luis Rodriguez Zapatero.
"You have to acknowledge reality. . . . When a lot more Spaniards don't vote than do, it's a failure for the person who called the referendum and that was the prime minister," said Angel Acebes, the number two leader in the Popular Party.
European Monetary Affairs Commissioner Joaquin Almunia, a Spanish Socialist, said that the turnout was "more than acceptable" and showed that Spaniards realized their future was with Europe. "The fact that it exceeded 40 percent . . . is positive, although it is true we would have liked a larger turnout," Almunia told state radio.
Zapatero has staked his reputation on making Spaniards, who joined the E.U. in 1986 and have benefited from membership, the first to approve the document.
The opposition has criticized Zapatero for rushing Spaniards to the polls and failing to sufficiently explain the constitution's contents. Polls showed that ignorance of the charter is widespread.
An exit poll commissioned by state television showed significant numbers of "no" votes in the Basque country and Catalonia, where small separatist parties had opposed the constitution, saying it did not recognize their regional identities. As many as a third of the voters opted for "no" in the Basque country and more than a quarter in Catalonia, according to the exit poll.
Nearly 35 million voters were eligible to answer the question: "Do you approve the treaty establishing a constitution for Europe?"
About 106,000 police officers were on alert for potential violence from the Basque separatist group ETA, but no incidents were reported. On Thursday, police arrested a man and woman in Valencia with explosives.
Unlike the British or Danes, the Spanish are friendly to the E.U. thanks to an economic boom associated with 86 billion euros, about $112 billion, of subsidies over the past 20 years.
The charter must be ratified by all 25 E.U. members to take effect and leaders had hoped Spain could set a good example for eight other countries due to hold referendums.
The referendum is not legally binding. Parliament still needs to ratify it, although Zapatero said he would respect public opinion.