In the last month, however, Army officers have said they see a long-term need for, at most, 10,000 of the MRAPs -- which cost $500,000 to $1 million apiece, depending on the model. Officers in Baghdad and Washington now are reevaluating whether they should ask Congress for money next year to buy more, or whether 10,000 is already too many.
Critics of defense budgeting believe the Pentagon and Congress rushed too quickly to embrace the MRAP as the best fix for the problem of roadside bombs.
"Congress latched onto this to show how pro-soldier and how pro-defense they were," said Winslow T. Wheeler, a longtime critic of military spending at the Center for Defense Information, a nonpartisan think tank. "It is another example of people thinking the way to address these conflicts is through technology. But that kind of thinking guarantees defeat in this kind of conflict."
Congressional MRAP advocates have argued that the short-term need to protect soldiers from roadside bombs far outweighs any long-term concerns about being stuck with expensive vehicles with limited uses.
"We might be stuck with a lot of these things that don't have a clear application in the next field of battle," said a Biden aide, who spoke on condition of anonymity, as is customary for congressional staffers. "But it doesn't matter. We're fighting the war we're in now, not the war we're going to fight in five or six years."
Pentagon officials said Gates expressed similar frustration in internal discussions, and he eventually ordered the Marines and the Army to make the program a priority. Gates also demanded weekly briefings to make sure they were making progress.
In his first year as Defense secretary, Gates has drawn a sharp contrast with his predecessor, Donald H. Rumsfeld, who had been criticized as moving too slowly to improve armor.
According to Francis J. Harvey, who was Army secretary during the early debates, MRAPs were a chance for Gates to move more decisively.
"I think he saw a way to differentiate himself from Rumsfeld," Harvey said. Harvey was forced to resign his post in March in the aftermath of revelations of deficiencies at Walter Reed Army Medical Center. Morrell, the Pentagon spokesman, said Gates was concerned not about comparisons with Rumsfeld, but about providing the best possible protection from improvised explosive devices.
"The MRAP program was driven by an urgent desire to protect U.S. forces from the No. 1 killer in Iraq -- IEDs," Morrell said. "That was the focus of the program."
'A fundamental error'
One result of the decision to rush MRAPs to Iraq is that they have not been thoroughly tested. The vehicle's ability to withstand bombings was extensively evaluated, but few infantry companies so far have tested its utility in counterinsurgency missions.
A Pentagon consultant who recently visited Iraq, in part to study the use of MRAPs, said the trucks protect troops and are useful for bomb disposal teams and commanders circulating in the battlefields. But the vehicles are not a good choice for combat infantry companies, the consultant said. They are too heavy to drive in soft sand and are difficult to turn on narrow streets.
"You have a pretty good anti-mine vehicle that has zero fighting ability, terrible off-road mobility, and can't turn around in a city," said the consultant, who was not authorized to discuss the findings and spoke on condition of anonymity. "The bottom line is that this MRAP is a fundamental error."
The concerns over the MRAP's abilities have increased inside the Pentagon. Some high-ranking officers worry that the price tag will lead congressional budgeters to cut funding for other weapons systems the Army believes are more important for the future.
Those pressures have led the Army to reconsider earlier proposals to replace all Humvees with MRAPs. Speakes, the Army procurement official, said he now sees the MRAP as a narrowly focused vehicle that can be used to clear mines and evacuate injured soldiers.
"We see niche roles for the MRAP, but we don't see that MRAP will ever be a dominant part of our tactical wheeled-vehicle fleet," Speakes said.
Nonetheless, critics said, the investment in MRAPs is too high and coming too late for Iraq.
"We went in the wrong direction," said retired Army Gen. Barry McCaffrey, who has advised the Bush administration on Iraq policy. "It is the wrong vehicle, too late, to fit a threat we were actually managing."