President Obama's plan to bring American troops home from Iraq is beginning to jell, but whether he keeps his campaign promise to do it in 16 months may depend on logistics, security needs in Afghanistan, and the political dynamic he confronts at the Pentagon.
Ultimately, the decision rests with the new commander in chief, who will either lean on a timeline-oriented departure to meet political goals or a conditions-based plan more pleasing to military commanders that could take two years or more.
Mr. Obama is expected to meet this week with the heads of the four services, including the Army and Marine Corps, who are eager to move beyond Iraq. Obama will weigh their views with those of senior commanders, including Gen. David Petraeus and Defense Secretary Robert Gates, both of whom are inclined to take more than 16 months to withdraw from Iraq.
"We have ... been looking at several options, and obviously 16 months is one of them," Mr. Gates told reporters Thursday.
The rate of departure may be first determined by what the president decides should now be the American security posture in Iraq. Many foreign-policy experts say the US has a strategic interest in leaving a sizable force there for years to come, and some believe that could mean as many as 60,000 troops remain in noncombat-related roles. The Bush administration has signed a "status of forces agreement" that requires most troops to be out of Iraq by 2011.
But other factors are at play. One is logistics: the ability to rapidly remove as many as 143,000 uniformed personnel, some 60,000 aircraft and vehicles, 120,000 trailer-sized containers, and 150,000 private contractors from nearly 50 bases and installations.
The military must decide what equipment stays and what goes. Gifting thousands of used Humvees or old generators to the Iraqis, for example, would cut down on what is shipped home. But it could also lead to more decisions about helping the Iraqis maintain the equipment. And then, who would pay for it?
The military has already been quietly moving materiel out of Iraq over the past 18 to 24 months, says a military official who requested anonymity. He adds, "We think right now we're about the right size we need to be."
The Marines have also been shipping as much as possible out of Iraq in anticipation of redeployment orders, Gen. James Conway, commandant of the Marine Corps, told reporters Friday. General Conway, who wants to send new forces to Afghanistan, has pushed for a reasonable but speedy redeployment. Obama is also looking to send more forces from Iraq to retool the mission in Afghanistan.
After the first Gulf War, an additional 6,000 National Guard and Reservists were sent to Kuwait to help get all the equipment out in about nine months, says Gus Pagonis, a so-called "logistical wizard" who, as a three-star Army general, oversaw the withdrawal from that conflict.
But Mr. Pagonis points out that he had "no terrorist threat and no threat of security." Withdrawal from Iraq, on the other hand, is expected to invite insurgent attacks and may require extra time.
Security will be on Obama's mind as he makes his decision. "The commander in chief cannot be political," says Pagonis. "To the average American, he is making the decision as president, but to the armed forces, he is making the decision as commander in chief."
If Obama slides on his 16-month withdrawal plans, he can use logistical and security concerns for political cover.
"Arguably, Iraqi security forces are improving fast enough that, absent a major disruption to the system, we could try to leave on Obama's 16-month schedule," says Michael O'Hanlon, a senior fellow at Brookings Institution, a think tank in Washington. But Mr. O'Hanlon says it would be a mistake to rush out of Iraq, ignoring the political realities, unresolved issues, and ethnic dissension that still exists there.
"The drawdown pace should be gradual this year and can then accelerate next year," he says.
More streamlined processes mean that Iraq does not have the "iron mountains" of stockpiled equipment that posed enormous logistical challenges in the first Gulf War, say military officials. Still, whatever decision Obama makes will require planners to move figurative mountains to get it done. "It will be tough, but it will not be insurmountable," says the military official.