TODAY, IRAQ stages a referendum on a constitution that most of its citizens have been unable to read. The document they will ratify or reject shifts crucial decisions about government, the judiciary and human rights to a future national assembly, and it may itself be rewritten in the first half of next year. Though planned as a landmark in Iraq's postwar reconstruction -- and still described that way by the Bush administration -- the referendum has been stripped of much of its substance. In the troubled Iraqi context, that amounts to good news.

Because it was rushed by a deadline-driven President Bush, the process of writing a constitution failed to produce an accord among Iraq's major factions about the country's future. Instead it yielded a draft that threatened to split the country and ignite a civil war. Fortunately, this deeply flawed document has been steadily devalued in backroom negotiations over the past six weeks, quietly brokered by the same U.S. administration that publicly compares the constitution drafters to those who met in Philadelphia in 1787.

The most important bargain was struck only on Tuesday. It provides for the establishment of a committee by the parliament to be elected in December to consider changes to the constitution next year. That deal led to the first crack in what had been universal opposition to the charter by the minority Sunni community, which is the main source of the armed insurgency U.S. troops are fighting. Though it's not the fundamental accord that the country needs, it provides more time for one, as well as the strongest signal yet that Sunni, Shiite and Kurdish leaders are capable of compromising with each other.

Whether that happens will depend partly on what happens today: whether, as widely predicted, Sunni voters turn out at the polls in large numbers after mostly boycotting last January's elections, and whether U.S. and Iraqi forces can protect them from insurgent attacks. Sunnis will probably oppose the constitution, despite its endorsement by one group of leaders, and the charter will probably be ratified anyway with Shiite and Kurdish votes. But Iraq's longtime ruling elite will at least have joined the democratic process. The question then will be: Will Sunnis mobilize again for the December parliamentary elections? Their participation in that vote will be crucial to creating a representative body in which deals can be hammered out.

Iraq's hopes also depend on the election in December of a larger group of secular and liberal Iraqis and a greater number of Shiites who oppose the separatism recently embraced by the most powerful Shiite leaders. This week's accord did not alter the refusal of those politicians to yield on constitutional provisions that would allow the creation of a nine-province Shiite ministate that would control Iraq's largest oil reserves and could emerge as an Islamic republic and Iranian client. Oddly, the incompetence and growing unpopularity of Iraq's present, Shiite-dominated national government could strengthen factions that favor holding the country together.

That, anyway, must be the hope of the Bush administration. Its true policy is hard to discern, given the disconnect between the president's surreal rhetoric -- which contrasts brave constitution writers with evil foreign terrorists -- and the actual situation, in which Shiites, Sunnis and Kurds compete for power by both political and military means. Increasingly, U.S. forces are trapped between implacable Sunni insurgents, whom the Americans fight with the help of a predominantly Shiite and Kurd Iraqi army, and intransigent Shiite and Kurd politicians, who depend on that U.S. defense to pursue political agendas that are at odds with a unified and democratic Iraq. The referendum won't resolve this dilemma, but this week's diplomacy has bought a few more months for the Bush administration to escape it. It can do that only by fostering a fuller Iraqi political compact, on or off a constitution's paper.