Local election officials in Diyala province say 70 percent of the 400,000 people who voted there in Saturday's referendum said "yes" to the draft constitution. Twenty-percent rejected it and 10 percent of the ballots were rejected as being irregular.
Sunni Arabs, who largely reject the constitution because they believe it gives too much power and oil wealth to rival Shi'ites and Kurds, form a majority in Diyala, Salahaddin and Nineveh provinces. But all three provinces have sizable populations of Shi'ites and Kurds, who mostly favor the constitution.
Without Diyala, Sunni Arabs now have a more difficult task reaching the two-thirds "no" vote in three provinces that would be required to nullify the constitution. That has raised concern that Sunni dissatisfaction over the charter could deepen sectarian and ethnic tension in Iraq, and strengthen the Sunni-led insurgency.
Sunni Arabs lost power and have felt marginalized since U.S.-led forces deposed Sunni dictator Saddam Hussein. Many Sunnis boycotted elections in January in protest, which brought Iraq's long-oppressed Shi'ites and Kurds to power.
Sunnis charge the country's new powerbrokers drew up the constitution with the intention of ignoring the Sunni people, and looking out only for their own communities. Sunni Arabs say that is a recipe for starting a civil war.
VOA spoke to about a dozen Sunni Arab residents who took part in Saturday's vote. Most said that they participated because they regretted boycotting January elections, and needed to feel politically relevant again.
The heavy turnout gave hope to some that enough Sunni Arabs voted "no" to defeat the constitution. Others said that they voted with the hope that their involvement in the political process will help undercut support for foreign Sunni extremists, like al-Qaida terrorist Abu Musab al-Zarqawi, and bring stability to Iraq.
Baghdad University student Haqqi Ismail says he voted simply because he did not agree with key points in the constitution. He also expressed the suspicion held by many Sunni Arabs that, however they voted, it will not matter, because the outcome of the referendum ultimately rests with the United States.
"If the counting of the votes is honest, and without any playing around, I think it will be defeated," he said. "But, if the Americans want it to pass, it will pass."
The U.S. ambassador to Iraq, Zalmay Khalilzad, who negotiated for months with Shi'ite and Kurdish leaders to formulate a document that would be inclusive of the Sunni religious community, says that is an unfair accusation.
"They have seen, I believe, the Sunni Arabs, from their interactions with the U.S. and the U.K. that we have been facilitating a fair process, in which everyone's interest is taken into account, and we have been encouraging compromises," he said. "At times, frankly, we have been advocates of their point of view with others."
If the constitution passes, Sunni Arabs have a chance to request changes in the charter after elections in December. The challenge of Sunni leaders now is to calm their followers, and focus on generating a huge turnout of voters in December, which will then allow Sunni Arabs to form a political bloc to be reckoned with.