All combat forces are scheduled to be out of Iraq by August, leaving only a residual contingent of 50,000 instructors to train Iraqi forces, advisers and other non-combat personnel on a string of bases.
The delay in parliamentary elections, originally scheduled for January but now put back to March because of intense political feuding, introduced some uncertainty concerning the withdrawal schedule.
U.S. commanders say the military is flexible and could start the final phase of the troop pullout as late as May if necessary.
But the logistics can't wait and so on Dec. 14, top-echelon logistics officers of the U.S. military gathered in Camp Arifjan in Kuwait, Iraq's southern neighbor, to map out their plans in a "rehearsal of concept" drill for moving everything from tanks to telephones out of Iraq by the August deadline.
Gen. Ray Odierno, the U.S. commander in Iraq, explained that this operation involves more than just putting troops on transport planes and flying them out.
"We have six years' worth of stuff that we've gathered here as the U.S. military," he says.
Since May more than 76,000 items of equipment and 10,000 vehicles have been shipped out, some of it to other units in the Central Command zone of operations around the Middle East and Afghanistan.
Most units are exceeding their objectives of moving out 300,000 containers a month, according to senior officers.
By the end of the withdrawal, military logistics teams will have moved an estimated 1.5 million pieces of equipment from some 300 bases around Iraq.
As the drawdown continues, logistics experts say the trick is to anticipate what those units still in place will require, such as food and fuel, and for how long. There are still some 100,000 troops in Iraq.
Among the accumulated machinery that has to be shipped out, there are some awkward items like the D-9 Caterpillar bulldozer, 48 tons of armor and engine. They have to be carried out on transporters to Kuwait for shipping.
The D-9 "will take out anything in its way," said Lt. Douglas Pelletier of the 87th Engineer Support Company. That includes road surfaces.
Then there's the mine-resistant, ambush-protected vehicle, a bulging, heavily armored truck designed to protect infantrymen from roadside bombs, one of the main causes of casualties throughout the war that began in March 2003.
"This thing weighs 58,500 pounds," says Spec. Ronnie Williams, who drives an MRAP.
Thousands of these ungainly vehicles will have to be hauled out on trailers called heavy-equipment transports over the desert border to Kuwait, from where they will be loaded onto ships for return to U.S. bases or on to reinforce U.S. forces in Afghanistan where a military surge is under way against the Taliban.
At the Camp Arifjan confab, the process was closely examined by the Third Army and 1st Theater Sustainment Command and a host of other concerned service and agency personnel, from the newly constituted U.S. Force-Iraq, Central Command, the Office of the Secretary of Defense, the Army Materiel Command, Defense Logistics Agency, the Joint Contracting Command for Iraq/Afghanistan and many others. Even the State Department had people there.
They held briefings and discussions on how this massive operation can be synchronized between dozens of units and locations. They also examined issues such as weather predictions, threat trends, customs operations, shutting down service stores and withdrawal timetables.
"The whole (drawdown effort) is staggering," said Col. Steven Elkins, the rehearsal of concept coordinator and 1st TSC support operations officer.
"We have a lot of capability because we've been doing this for a number of years now. But it's like reversing a faucet."
Notable deaths of 2014 [PHOTOS]