Sunni Arabs voted in surprisingly high numbers on Iraq's new constitution, many of them hoping to defeat it in an intense competition with Shi'ites and Kurds over the shape of the nation's young democracy after decades of dictatorship. With little violence, turnout was more than 66 percent in the three most crucial provinces. The constitution still seemed likely to pass, as expected. But the large Sunni turnout made it possible that the vote would be close or even go the other way, and late Saturday it appeared that at least two of a required three provinces might reject it by a wide margin. Washington hopes the constitution will be approved so that Iraqis can form a legitimate, representative government, tame the insurgency and enable the 150,000 US troops to begin to withdraw. After polls opened at 7 a.m., whole families turned out at voting stations, with parents carrying young children, sometimes in holiday clothes. Men and women lined up by the hundreds in some places or kept up a constant traffic into heavily bunkered polls, dressed in their best in suits and ties or neatly pressed veils - or in shorts and flip-flops, weary from the day's Ramadan fast. "I'm 75 years old. Everything is finished for me. But I'm going to vote because I want a good future for my children," Said Ahmad Fliha said after walking up a hill with the help of a relative and a soldier to a polling site in Haditha, a western Sunni town. Some 9 million Iraqis cast ballots, election officials said, announcing a preliminary turnout estimate of 61%. In Baghdad, men counted votes by lanterns because the electricity was out in parts of the city. Results were written on a chalkboard. Outside, Iraqi soldiers huddled in a courtyard, breaking their fast. Northeast of the capital, in Baqouba, men sat around long tables, putting "yes" votes in one pile and "no" votes in another. A day that US and Iraqi leaders feared could become bloody turned out to be the most peaceful in months, amid a heavy clampdown by US-Iraqi forces across the country. Insurgents attacked five of Baghdad's 1,200 polling stations, wounding seven voters, but there were no suicide bombings or other major attacks. Four Iraqi soldiers were reported killed by attacks far from polling sites - compared to the more than 100 attacks that hit January parliamentary elections, killing more than 40 people. "The constitution is a sign of civilization," Prime Minister Ibrahim al-Jaafari said after casting his ballot. "This constitution has come after heavy sacrifices. It is a new birth." The country's Shi'ite majority - some 60% of its estimated 27 million people - and the Kurds - another 20% - largely support the approximately 140-article charter, which provides them with autonomy in the northern and southern regions where they are concentrated. The Sunni Arab minority, which dominated the country under Saddam Hussein and forms the backbone of the insurgency, widely opposes the draft, convinced its federalist system will tear the country into Shi'ite and Kurdish mini-states in the south and north, leaving Sunnis in an impoverished center. Most Sunnis appeared to be voting "no" even after one major party, the Iraqi Islamic Party, came out in support of the draft because last-minute amendments promised Sunnis the chance to try to change the charter later. "We have entered the political process now because our rights were being usurped by others who have marginalized us," said Sunni Hazem Jassim, 45, referring to Iraq's other factions. The bar for Sunni opponents to defeat the constitution is high: They must get a two-thirds "no" vote in any three of Iraq's 18 provinces. They were likely to reach that threshold in the vast Sunni heartland of Anbar province in the west. They must snatch the two others among the provinces of Salahuddin, Ninevah or Diyala, north of Baghdad. By late Saturday, Salahuddin appeared to be nearing a two-thirds "no" vote after an overwhelming showing at the polls in Tikrit, Saddam's hometown, where some election officials said 90 percent of the voters cast ballots. There were no figures on Ninevah or Diyala, but those are considered harder for Sunnis to win. Each of those provinces has a Sunni Arab majority, but they also have significant Shi'ite or Kurdish minorities. Competition was fierce in all three, with some of the highest turnout rates in the country - well above 66%. In the south, Shi'ite women in head-to-toe veils and men emerged from the poll stations flashing victory signs with fingers stained with violet ink, apparently responding in mass to the call by their top cleric, Grand Ayatollah Ali al-Sistani, to support the charter. "Today, I came to vote because I am tired of terrorists, and I want the country to be safe again," said Zeinab Sahib, a 30-year-old mother of three, one of the first voters at a school in the mainly Shi'ite neighborhood of Karrada in Baghdad. Voters flowed constantly into a kindergarten used as a polling site in a Sunni Arab district of Mosul, Ninevah's capital. "The government can't just sew together an outfit and dress the people up by force. We do not see ourselves or see our future in this draft," Gazwan Abdul Sattar, 27-year-old Sunni teacher, said after voting "no." But in a nearby district, Kurds lined up as well, some decked out in tradition garb of baggy pants and belted vests, or wrapped in the red-and-green Kurdish flag, emblazoned with a yellow sun. "This document serves the ambitions of the Kurdish nation and we hope then that we will be able to determine our destiny in the future," said Barzan Berwari, a 45-year-old businessman. In Tikrit, Saddam's hometown, voting was intense. "This constitution was written by people who are loyal to Iran rather than being loyal to Iraq," said Hassan Maajoun, 60, reflecting some Shi'ites' deep suspicion of Sunni ties to neighboring Iran. But voting was just as heated in the smaller Shi'ite towns in the southern part of the province as they raced to stop the Sunnis short. After placing the ballots in the plastic boxes at the polling centers, Iraqis had the forefinger of their right hands marked with violet ink to prevent repeat voting. About 250 of the country's 6,100 polling stations, mostly in the north and west, did not open because of technical or security problems, elections officials said. The polls opened just hours after government workers restored power lines that insurgents sabotaged in the north Friday night, plunging the Iraqi capital and surrounding areas into darkness. When voting ended 10 hours later, celebratory gunfire rang out in Baghdad streets, and some families handed out sweets to passers-by. While turnout was high in the mixed areas, Shi'ites in the south and Kurds in their autonomous enclave in the north showed less enthusiasm, with fewer than 66% of voters showing up in most of the provinces in those areas - likely reflecting the feeling that a "yes" vote was a sure bet there. Less than a third of voters in the region around the city of Ameriyah bothered to show up. Turnout in January's vote was 58%, but Sunnis largely boycotted that election while Shi'ites turned out in droves, celebrating their chance to dominate the new government. Bush administration officials said they were pleased that Iraqis appeared peaceful and enthusiastic about exercising their right to vote. "Today's vote deals a severe blow to the ambitions of the terrorists and sends a clear message to the world that the people of Iraq will decide the future of their country through peaceful elections, not violent insurgency," White House spokesman Allen Abney said. Whether the charter passes or fails, Sunnis appeared to throw themselves wholeheartedly into a political process that until now they have been deeply suspicious of. That could indicate they will try more in the future to work within a system US and Iraqi leaders hope can moderate the country's vicious sectarian divisions. But if the constitution passes despite a significant Sunni "no" vote, hard-liners in the community could decide the insurgency is their only hope to retain influence in the country. In the Sunni Anbar province, streets and polling stations in towns strung along the Euphrates River valley were largely empty as residents remained hunkered in their homes, fearing insurgent violence or so embittered they refused to vote. The minimal turnout in Anbar - as in the January election - suggested the key battleground between US-Iraqi forces and insurgents, would remain alienated from the political process. But voting was not along sectarian lines everywhere. In Sadr City, a mostly Shi'ite area of Baghdad controlled by radical cleric Muqtada al-Sadr, who led uprisings against the US-led coalition last year, people were widely expected to vote "yes." Not Haitham Aouda Abdul-Nabi, a 23-year-old co-owner of a convenience store. When he showed up at a Sadr City secondary school to vote, he said: "More than 90% of Iraq's Shi'ites support the constitution, but not me." Why? Because he is tired of the chaos that has followed Saddam's ouster: killings by insurgents, fighting between rebels and US troops, squabbling in Iraq's mostly Shi'ite and Kurdish government, and nearly daily power outages in the capital. "Only force can bring results with a people like us in Iraq," he said. "Unfortunately, we need someone like Saddam. This government is too weak."