The chances for Iraq's draft constitution to be approved in Saturday's referendum seem to have improved after the country's main Sunni Arab political party agreed to support the document. Last minute negotiations Tuesday between, Sunni, Shi'ite and Kurdish political leaders produced a tentative accord, which would allow the constitution to be amended early next year, has revived hopes of greater Sunni participation in Iraq's political life -- a development that could eventually undermine the country's violent insurgency.

As copies of Iraq's draft constitution are distributed and studied, the country's main political leaders have reached an agreement aimed at persuading the once-dominant Arab Sunni minority to endorse the document.

Sunnis strongly object to provisions of the constitution that would turn Iraq into a loose federation with a weak central government.  They fear if the charter is passed, it will divide Iraq -- leaving Shi'ites in the south and Kurds in the north in control of the nation's oil revenues.

But political leaders have agreed to create a panel in the next parliament that would propose broad changes to the constitution.  This would give the Sunnis a new chance to help rewrite the document after elections in December.

Sunnis had largely been excluded from drafting the constitution because they boycotted the January elections. As a result, Shi'ites and Kurds won control of the national assembly and government and were instrumental in drafting the constitution.

But it is unclear if this latest accord will lead more Sunnis to vote "yes" in Saturday's referendum, according to Middle East expert Marina Ottoway of the Carnegie Foundation in Washington. "There are politicians, Sunni politicians, who have understood that the policy they followed last January, that is, boycotting all the political processes is leading them down a blind alley.  They boycotted the elections and as a result the train left the station without them, they found themselves as a small minority in the parliament with very little voice in writing the constitution, and so on.  So there is certainly a certain political stratum there that is willing to play by the rules to try to become part of this process.  How much following do they have? We have no idea."

Sunni turnout Saturday in favor of the constitution could be key. A two-thirds "no" vote in any three provinces would be enough to overturn the charter and the Sunni Arab population is concentrated in four of Iraq's 18 provinces.

The prospect of amending the constitution could spur Sunni Arabs to participate more fully in Iraq's political life.

This, in turn, could eventually undercut support for the insurgency, according to Ms. Ottoway. "It is something that could happen in the long-run.  I don't think the hard-core, the leaders of the insurgents, are going to change their position just because there is a constitution.  I mean this is really a hard-core group that is fighting.  Look at what they are doing on the ground and you realize this is really a very hard-core group. So, in the short-run I don't think it's going to convince the hard-core.  What it might do is start to decrease popular support or popular tolerance for the insurgents -- that might happen over a period of time." 

The breakthrough agreement was a major victory for American officials, especially U.S. ambassador Zalmay Khalilzad who reportedly was instrumental in pushing for negotiations and compromise.

At the White House, spokesman Scott McClellan welcomed the accord.

"We view the agreement that was reached as something very positive, we welcome it. What we have always encouraged is that the political process be as inclusive as possible.  That's what we've emphasized and we believe that these steps will help Iraq move forward on the path to a strong and lasting democracy."

Despite the agreement, insurgent violence is expected to continue.  Terrorists have vowed to continue bombings and other attacks against civilians in an effort to derail Saturday's vote and provoke a civil war between Sunnis and Shi'ites. 

Meanwhile, Iraqi's, including Sunnis, have registered to vote in overwhelming numbers.  Some 15 million Iraqis are registered to take part in Saturday's referendum.