WASHINGTON — Defense Secretary Robert M. Gates said Thursday that it was unclear how long the current buildup of U.S. forces in Baghdad would last and that commanders would have to wait until midsummer to evaluate whether it was working.
Gates has said he hopes to end the deployment of 21,500 additional combat troops and thousands of support personnel by December. But in recent weeks, some senior officers, including the Army general in charge of day-to-day operations in Iraq, have suggested that the so-called surge may have to be extended into early next year. The recommendation is being debated by senior commanders.
At a Pentagon news conference, Gates did not directly address a suggestion by Lt. Gen. Raymond T. Odierno, the operations commander, to maintain the higher troop levels. He said any decisions on troop numbers would depend on progress on the ground.
"The truth is, I think people don't know right now how long this will last," Gates said. "The thinking of those involved in the process was that it would be a period of months, not a period of years, or a year and a half or something like that."
The duration of the troop buildup has become an issue of increasing political rancor as congressional Democrats have attempted to force the Bush administration to begin a withdrawal of U.S. forces from Iraq. The White House and Congress are on a collision course over war funding and troop levels, with President Bush pledging to veto legislation requiring him to start bringing troops home.
The boost in troops ordered by Bush in January has increased burdens on an already stretched Army. Three major units are being deployed as part of the new plan without the standard yearlong stays at their home bases.
In January, Gates adjusted Pentagon deployment policies to allow for more frequent call-ups of the National Guard, a step intended to relieve some of the stress on active-duty Army units. But he acknowledged Thursday that even with the new policy, more combat brigades might be forced to serve extended deployments and others might find their "dwell time" at home shortened.
"I think we always anticipated ... that there would be a transition time when there would be both extensions and violation of dwell policy, just because of the magnitude of the commitments that we have," Gates said, adding that it was "very possible" such hardships could last for another year or two.
Marine Gen. Peter Pace, chairman of the Joint Chiefs of Staff, said shortened home stays cut into training time, meaning that some units would be given only urgently needed training rather than the "full spectrum" of tactics normally provided.
"You end up with your troops who are well trained for the mission they're going to, but you do forfeit some of the kind of training you would like to do just to have a little bit more readiness in case something happens that you're not expecting," Pace said at the same news conference.
Other members of the Joint Chiefs have raised such concerns, including Gen. James T. Conway, commandant of the Marine Corps. Conway said he was concerned that Marines were increasingly unprepared for rapid landings and attacks common in the early days of a crisis, which has been their primary mission in the past.
Even shortened, the training schedules have hampered the Pentagon's ability to send troops to Iraq for the buildup as quickly as it would like, Gates said. Under the current schedule, all five Army brigades that are part of the new plan are to arrive no earlier than June.
Gates said war planners had attempted to accelerate the deployments. But the military's inability to move equipment to the region more quickly and the need to keep units on a regular training routine forced a slower schedule, he said.
"One of the principal reasons that it was not possible to accelerate it was that we want to make sure that every single one of those brigades is adequately trained before they actually enter Iraq," he said.