Barring any major surprises in Iraq, the Pentagon tentatively plans to reduce the number of U.S. forces there early next year by as many as three combat brigades, from 18 now, but to keep at least one brigade "on call" in Kuwait in case more troops are needed quickly, several senior military officers said.
Pentagon authorities also have set a series of "decision points" during 2006 to consider further force cuts that, under a "moderately optimistic" scenario, would drop the total number of troops from more than 150,000 now to fewer than 100,000, including 10 combat brigades, by the end of the year, the officers said.
Despite an intensified congressional debate about a withdrawal timetable after last week's call by Rep. John P. Murtha (D-Pa.) for a quick pullout, administration officials say that military and political factors heavily constrain how fast U.S. forces should leave. They cite a continuing need to assist Iraq's fledgling security forces, ensure establishment of a permanent government, suppress the insurgency and reduce the potential for civil war.
U.S. military commanders, too, continue to favor a gradual, phased reduction, saying that too rapid a departure would sacrifice strategic gains made over the past 30 months and provide a propaganda windfall to insurgents.
Lt. Gen. John R. Vines, the senior tactical commander in Iraq, indicated to reporters at the Pentagon yesterday that his staff had looked at shrinking U.S. force levels more quickly. But he made his opposition to such a move clear.
"A precipitous pullout, I believe, would be destabilizing," Vines said from Baghdad.
Another senior general likened an accelerated withdrawal to "taking the training wheels off of a bike too early," warning that a sudden removal of all U.S. troops would risk the collapse of Iraq's fledgling security forces. He and several other officers privy to the planning for force reductions said the process has not been affected by the mounting political pressure in the United States and among some Iraqi leaders for U.S. troops to leave.
The current number of U.S. forces in Iraq represents an increase of more than 15,000 troops over a base level this year of about 138,000, including 17 combat brigades. The equivalent of another brigade's worth of combat power was added this fall to bolster security for the Oct. 15 constitutional referendum and the coming Dec. 15 vote on a new national government.
Defense Secretary Donald H. Rumsfeld spoke over the weekend of plans to bring the force level back down to 138,000 after the elections, effectively removing the extra brigade equivalent added for the election period.
In addition, officers said, two combat brigades that had been slated to move into Iraq to replace units coming out are now expected to be held back. One of those units -- a brigade of the 1st Armored Division based in Germany -- will probably be positioned in Kuwait. The other unit -- a brigade of the 1st Infantry Division -- will probably remain at its home base of Fort Riley, Kan., the officers said.
The plan to keep at least one brigade in Kuwait represents what one senior officer called a "hybrid option." It is intended to hedge against events in Iraq deteriorating once U.S. force levels begin to drop, the officer said, adding that the Pentagon probably will place troops on alert elsewhere as well.
"These would be middle measures that would allow for a mitigation of the risks of reducing forces in Iraq and make the decisions more palatable," the officer said.
Murtha, in his call for withdrawal last week, also suggested retaining a quick-reaction force in the region as well as Marines within a short sailing time away. Similarly, in an article published by the Center for American Progress last month, Lawrence J. Korb and Brian Katulis, two defense specialists, outlined a plan for redeploying some U.S. forces from Iraq to Kuwait and offshore in the Persian Gulf.
One general involved in the planning said there is some concern about avoiding a perception that the United States, by shifting forces to Kuwait that were intended for Iraq, is beginning a new military buildup in the region.
"We prefer to describe it as shifting troops forward to the region, not building up a force on the border with Iraq," the general said.
All the officers who spoke about the troop plans stressed that final decisions will come only after the Dec. 15 vote. But they described the moves as likely, assuming no major turn for the worse in Iraq. They spoke on the condition of anonymity because they had not been authorized to discuss the plans. They also were unable to provide an exact figure for how many troops would remain in Iraq after the initial reductions take effect next year.
Military officers and defense officials have frequently described the challenge of deciding how many forces to keep in Iraq as a balancing act between trying to provide security and avoiding the appearance of an occupation force that may fuel insurgent violence and engender Iraqi dependence on U.S. assistance.
"The tension that the commanders feel between heavy presence and lower footprint is something they're measuring all the time," Lawrence T. Di Rita, the Pentagon's primary spokesman, said yesterday.
To help gauge the particular impact that growth of Iraq's security forces might have on the pace of a U.S. drawdown, military planners in Baghdad have devised a simple formula -- what one general called a "rough rule of thumb."
The formula estimates that for every three Iraqi battalions and one Iraqi brigade headquarters achieving a readiness rating of level two, a U.S. battalion can be dropped. A level two rating, on a scale of one to four, indicates that a unit is able to take the lead in operations but still requires some U.S. military support.
The withdrawal formula is a planning tool, several officers stressed, not a definitive predictor of how many U.S. forces are likely to leave, or when.
The Iraqi military has experienced rapid growth in combat units this year, but it continues to suffer from much slower development of transportation, engineering and other critical support elements. That will require U.S. forces to provide backup for months, U.S. officers said.
There are also concerns about Iraq's new police force and the presence of militias. Last week, U.S. troops discovered a secret Interior Ministry facility holding more than 170 detainees, many of whom said they had been treated badly. It had been run by members of the Badr Brigade, a Shiite militia loyal to Iraq's largest political faction.
"What it illustrates is that we have failed to form a unified police force," said a U.S. official involved in Iraq policy. "There are now militias all over Iraq that operate freely and as an arm of political coercion."
Iraq's political timetable also will require a substantial U.S. presence next year, officials say. After the Dec. 15 election, Iraqis will need time to form a new government -- that took more than three months after January's vote. The new parliament is then to begin a four-month process of amending the constitution approved in October. Iraqis will then vote in another constitutional referendum.
"The reconciliation process will span a long period of time," said a White House official. "They have significant political benchmarks for the next six months or longer, and we anticipate they'll want us to play an important role in facilitation."