As it turned out, it was months before the command’s planners began to receive some of the clarification they were hoping for. The Bush administration put aside the idea of establishing a prewar provisional government for fear it would marginalize Iraqi leaders who had not gone into exile. Colonel Agoglia said he did not begin to get a sense of what the postwar arrangements would be until Jay Garner, a retired three-star general, was tapped by the Bush administration in January 2003 to serve as the first civilian administrator in postwar Iraq.

Another assumption spelled out in the PowerPoint presentation was that “co-opted” Iraqi Army units would heed the American appeals to stay in their garrisons and later help United States to secure the country.

Based on this and other hopeful suppositions, the command’s planners projected what the American occupation of Iraq might look like. After the main fighting was over, there was to be a two- to three-month “stabilization” phase, then an 18- to 24-month “recovery” phase.

That was to be followed by a 12- to 18-month “transition” phase. At the end of this stage — 32 to 45 months after the invasion began — it was projected that the United States would have only 5,000 troops in Iraq.

Now, those projections seem startlingly unrealistic given the current troop buildup, in which the United States currently has about 132,000 troops in Iraq and is adding about 20,000 more. But the projections, former military planners say, were intended to send the message to civilian policy makers that the invasion of Iraq would be a multiyear proposition, not an easy in-and-out war.

As it turned out, the assumptions on Iraqi and American forces were quickly overturned, partly as a result of new American policy decisions. Instead of staying in garrisons, many of the Iraqi soldiers fled after the war began. Senior American commanders hoped to quickly recall the Iraqi troops to duty anyway, but that option vanished in May 2003 when L. Paul Bremer III, Mr. Garner’s successor, issued an edict formally disbanding the Iraqi Army.

The message that the United States should gird itself for a substantial multiyear occupation seemed to be superseded when General Franks issued new guidance to his commanders a week after the fall of Baghdad on April 9 that they should be prepared to reduce the American troops in Iraq to a little more than a division by September 2003 — some 30,000 troops.

A series of ad hoc decisions and strategy changes followed as the insurgency grew and security deteriorated. A new military plan is now being put into effect, which the White House asserts may yet salvage a positive outcome. Almost four years after the invasion, however, the “stable democratic Iraqi government” the United States once hoped for seems to exist only in the command’s old planning slides.