With the exception mostly of two brigades of about 8,000 troops who would remain in the touchy Kurdish region in the north for a year to guard against conflict with Turkey, the U.S. troops would be moved to Kuwait initially, says the study by the Center for American Progress, a self-described "progressive think tank" headed by John D. Podesta, a former chief of staff to former President Clinton.
A brigade and an air wing of some 70 to 80 planes would remain in the Persian Gulf country indefinitely. Meanwhile, the withdrawal would give the United States leeway to add 20,000 troops to the 25,000 in Afghanistan trying to counter Taliban and al Qaeda forces.
How fast the troops depart from Iraq and go home depends largely on how much essential equipment goes along with the withdrawal, according to the study.
The troops could be out of Iraq in no more than three months if the equipment is left behind, a course not proposed in the study.
On the other hand, "if the United States does not set a specific timetable, our military forces and our overall national security will remain hostage to events on the ground in Iraq," the report said.
Even worse, an all-out civil war could compel a withdrawal of the U.S. troops, now numbering about 160,000, in three months' time, which would force leaving valuable equipment behind and preventing control of an orderly exodus, the report said.
The Bush administration is expected to disclose next month how large a withdrawal it contemplates and over what period of time. No consensus on when to begin and how deeply to cut has developed.
Lawrence Korb, a former Pentagon official who specialized in manpower and logistics there from 1981 to 1985, said in an interview: "It is essential that the military begin planning for a phased withdrawal from Iraq now so it can be safely completed within 10 to 12 months."
Korb, one of the authors of the report, said withdrawal proposals have varied from three months to four years.
The center's recommendation for withdrawal over a period of 10 to 12 months is based on consultation with military planners and logistics experts, the report said.
It proposed removing two combat brigades from Iraq a month while simultaneously reducing a proportional number of non-combat support personnel.
If the plan is adopted and U.S. combat units deployed in Iraq were not replaced as they went home the Bush administration could conclude the withdrawal by the end of next July "and with much more care than they did the invasion and occupation," the report said.
"The time for half-measures and experiments is over; it is now time for a logistically sound strategic redeployment," the report concluded.
At a news conference Wednesday, Korb said more than 100,000 Iraqis who helped the United States during the occupation should be taken out of the country, as well.
Their evacuation is a "moral responsibility," he said, and "there is no reason they cannot be resettled in the United States easily."