FORT POLK, La. — For weeks, the 1st Cavalry Division's "Grey Wolf" brigade has slogged the forests of central Louisiana in a final round of combat training -- tightening the bowstring one last notch before its scheduled departure for Iraq.
Bone-weary but keyed up and ready, the brigade's 3,800 soldiers are part of the stream of troops moving down a vast assembly line created by the Pentagon to train and transport the tens of thousands rotating into and out of Iraq and Afghanistan.
At the same time, defense officials have begun to plan for the possible phased reduction of U.S. forces in Iraq. By the end of the year, the number of troops there could drop by as many as 30,000.
So soldiers continue to train as though tomorrow will be their own personal D-day, knowing all the while that they might end up going home instead. As a result, the soldiers, their families and the U.S. military as a whole are faced with often-difficult adjustments.
"There's tremendous mental preparation ahead of deployment," said Michele Flournoy, an analyst with the Center for Strategic and International Studies who has worked on readiness issues at the Pentagon. "To go through all that preparation and then be told, 'No, sorry, you're not going,' and then, in many instances, be told two months later you are going is very difficult psychologically and emotionally," Flournoy said.
From a logistical point of view, the deployment system involves so many long-range plans and commitments that asking it to pause or run in place is like asking a space shuttle and its crew to launch but circle overhead while headquarters decides whether to send it on its way.
"The Bush administration desperately wants to draw down the military presence in Iraq, but it is unable to begin that process until it is confident a disaster won't follow," said Loren Thompson, a military analyst at the Lexington Institute with close ties to the Pentagon. "The American soldier is going to be in the middle of that for a long time to come."
Said Army Staff Sgt. Cody Choate, sweat dripping down his face as he stood in the muggy bayou heat at Fort Polk one recent day: "If you start thinking you're not going, when it really happens, you're going to be in the mud."
For now, in the mud is where Choate and the rest of the Grey Wolf brigade are anyway.
For almost a month, they have been at Fort Polk, home to the Joint Readiness Training Center -- one of two facilities in the United States that the Army has developed for last-minute training of units headed into combat. A total of 28 brigades have come through Fort Polk's 190,000-acre facility since the wars in Afghanistan and Iraq began, at a cost of $9 million for each monthlong session.
Over the last three years, Polk has transformed itself into a replica of what American units are likely to encounter in Iraq, complete with 18 small villages populated by more than 700 "role players" who act as Iraqi civilians.
When a simulated car bomb erupted here recently in a cataclysm of smoke, flames and screaming wounded, Choate -- who has already survived three overseas deployments -- said it "scared me more than anything I've been through in Iraq."
Col. David Sutherland, the Grey Wolf brigade commander, said his troops actually started getting ready to deploy in January, with a monthlong evaluation exercise at their home base of Fort Hood, Texas. The brigade needed work on some traditional combat skills, marksmanship and medical treatment. But it also needed to hone skills that were more Iraq-specific, such as handling detainees and developing what Sutherland called "intense cultural awareness."
Now the brigade is not sure it will even go to Iraq, although Army officials said it is officially slotted to replace units of the 4th Infantry Division, which is in Baghdad and urban areas just south.
Being in limbo can be even tougher for spouses and families than for soldiers.
"It's an emotional roller coaster," said Michelle Joyner, a member of a military family group. "To find out you're not going is a relief, but sometimes the families turn around months later and find out they are going."
The National Military Family Assn., a nonprofit group that represents soldiers' spouses, has conducted two surveys since the start of the Iraq war -- both of which showed that unpredictability over when soldiers will be sent overseas is one of the primary sources of familial stress.
Ironically, it was partly to reduce the uncertainty that the Army began to develop long-term deployment schedules. In the case of the Grey Wolf brigade, commanders have known since late 2005 that they were projected to arrive in Iraq in October.
In the first outward sign that the Army is beginning to retool long-planned Iraq rotations, the Pentagon this month announced that it was delaying the deployment of a Germany-based brigade. The news came just days before soldiers were scheduled to ship out.