The announcement of a firm date to create an interim Iraqi government and end the formal American occupation - though not the American military presence - promises the Iraqis the sovereignty they have clamored for, and offers President Bush the political symbol he needed: the beginnings of an exit strategy that he can explain to American voters.

But the price of a speedy transfer of power, Mr. Bush's own top aides worry, may be a rapid loss of control - control over the drafting of a constitution, and over the effort to make democracy flower in a land where it had never been cultivated. Now that Mr. Bush himself has redefined America's mission in Iraq - from disarming Saddam Hussein to creating "a free and democratic society" that will be a model for the rest of the Middle East - any plan that grants Iraq its sovereignty before it adopts full-fledged democracy risks derailing that grander mission.

"It's a gamble, a huge gamble," one of the most senior architects of Mr. Bush's campaign to oust Saddam Hussein conceded this week, after two days of meetings with L. Paul Bremer III, the head of the American-led occupation authority. "But it's easy to overestimate the degree of control we have over events now," the official said, "and to underestimate how much we will retain."

If the plan succeeds, Mr. Bush could declare an end the formal American occupation of Iraq by early summer, just as the presidential campaign heads into its final and decisive stretch.

But American officials expect that tens of thousands of allied troops will remain at the new government's "invitation," and nobody can predict whether they will still face a violent and deadly insurgency, possibly targeting Iraqi security forces as well. That would make it harder for Mr. Bush to describe the transfer of power to a new government, and the drawing down of American troops, as an unqualified success.

Aside from its continuing military presence - the United States will continue to flex its financial muscle as it doles out $20 billion in rebuilding aid and oversees billions more in private investments in the country.

But the combination of an intensifying insurgency and rapidly eroding Iraqi support for the American occupation left President Bush few options but to loosen his grip over the nation that he had conquered and is now trying to rebuild.

So in the past week, an administration that is loath to admit any doubts about the wisdom of its judgments basically rewrote its strategy.

Administration officials have dismissed critics who suggest that the process might be driven by Mr. Bush's electoral needs, taking pains to portray the new approach as Iraqi-born, initiated by Iraqi leaders out of what Condoleezza Rice, the national security adviser, called a "clamor" for a faster turnover of power.

Yet until sometime in the past few weeks, Mr. Bremer argued internally that the Iraqis were not ready to assume full authority, and that turning it over before the basic outlines of Iraqi democracy were established would invite chaos, or worse.

During his abruptly scheduled meetings at the White House on Tuesday and Wednesday, Mr. Bremer delivered the news that the fractious Iraqi Governing Council was approaching rebellion over the plan to draft a constitution first and to transfer power only after national elections. It was an approach that was straightforward, logical, deeply rooted in the history of the occupations of Japan and Germany, and untenable on the streets of Baghdad.