With U.S. mediation, Shi'ite and Kurdish politicians in Iraq are meeting with Sunni Arab leaders, searching for possible last-minute changes to Iraq's draft constitution in order to win Sunni support.  As the negotiations continue, Sunni Arabs are preparing to vote down a charter they say is biased against them. 

Neatly stacking bags of dates, freshly picked from a nearby grove, a shopkeeper in the town of Tarmiyah is at first reluctant to be interviewed by a Western reporter about whether he will participate in Saturday's referendum on the country's constitution. 

Looking furtively around him, the shopkeeper, who identifies himself only as Hamza, says it is dangerous for him to be seen speaking to a foreigner. 

But when pressed to give an answer, he quickly says that he and his friends have already thrown copies of the constitution in the trash.

Located between Baghdad and city of Samarra to the north, Tarmiyah and its surrounding countryside has long been an enclave for some of the most die-hard Sunni Arab supporters of Iraq's former dictator Saddam Hussein.

When U.S.-led forces deposed the dictator and disbanded the Iraqi army in 2003, unemployed and disgruntled Sunnis and Saddam loyalists turned the area into one of the hotbeds of the insurgency. 

Feeling marginalized and threatened with violence by Sunni Muslim extremists who oppose democracy in Iraq, many Sunni Arabs here joined other disaffected Sunnis in boycotting national elections in January.  The boycott handed control of the 275-member parliament to Iraq's long-oppressed Shi'ites and Kurds, who largely wrote and then approved the new draft constitution.

Another shopkeeper in Tarmiyah, who identifies himself as Jassem, says most Sunnis now realize that boycotting January elections was a huge mistake because it gave Shi'ites and Kurds the power to write a constitution, which he says deliberately ignores the Sunni people.

Mr. Jassem says the constitution is vague on what is going to happen to Iraq's oil wealth.  The shopkeeper says all he knows is that most of the country's oil is in the Kurdish north and in the south of the country, where Shi'ites want to form a semi-autonomous mini-state so that they can keep the oil revenue for themselves.

Mr. Jassem is referring to a clause in the draft constitution that endorses an arrangement that gives strong power to regional governments.  Sunnis fear that a loosely federated system will deprive Sunni-Arab regions of the benefits of Iraq's vast oil reserves and cause the country to break apart.

Sunnis also object to several other key points in the constitution, including the document's blunt language outlawing Saddam's Ba'ath Party as a terrorist group.  Since many Sunnis are former Ba'ath Party members, they fear the provision could be used to purge, and then to exclude, Sunnis from government jobs.

Under existing law, a no vote by a two-thirds majority in any three provinces in Iraq would defeat the referendum.

The three-province veto rule was actually a concession to the Kurds during negotiations for the interim constitution in March, 2004.  The Kurds, who form a majority in three provinces in the north, wanted the ability to reject the constitution if they did not approve of it. 

Now, it is the Sunni Arabs who see the veto rule as their best chance to vote down the charter.

Sunnis, who make up about 20 percent of Iraq's 27 million people, form the majority in four of the country's 18 provinces. 

The very Sunni leaders and clerics, who denounced the January elections as a farce orchestrated by foreign occupiers, are urging their people to ignore Sunni extremists threats and to go to the polls.

Extremist groups, led by al-Qaida in Iraq, have declared Iraq's democratic process un-Islamic and have threatened to kill Sunnis who participate.

A man appearing in an advertisement on Iraq's Sharqiyah television channel tells its mostly-Sunni audience that only stupid and weak people believe foreign terrorists who say they are acting on behalf of the Sunni people.  The man says it is up to Iraqi Sunnis to decide their fate and to vote no in the referendum.

That message appears to have already reached a large segment of Iraq's Sunni population, even those who acknowledge that they have not read any part of the constitution. 

Tarmiyah resident Amir Hailu, says he knows nothing about the charter, but he has already decided to vote against it.

Mr. Hailu says that he has not yet been able to get a copy of the constitution.  And with only a few days left before voting day, there is not enough to study it even if he did find a copy.  He says he will vote no because that is what the majority of other Sunni Arabs are going to do.

If the constitution fails, Iraq's interim parliament will have to be dissolved and elections for a new one held by December 15.  The new assembly would then have to work on another constitution to be put to a referendum next October.

But many Iraq analysts say they believe Sunni Arabs will not be able to muster enough votes to defeat the charter.  Sunnis may form the majority in four of the country's 18 provinces, but their numbers are overwhelming in only one.

Most people, even Sunni Muslims opposed to it, say the constitution is likely to pass.  And that has led to fears that the referendum may only further distance Sunni Arabs and strengthen the insurgency.