Some in Congress and others outside the Army are beginning to question the switch, which is not widely known. They wonder whether it means the Army is cutting corners in preparing soldiers for combat, since they are forgoing training in a desert setting that was designed specially to prepare them for the challenges of Iraq.
Army officials say the two brigades will be as ready as any others that deploy to Iraq, even though they will not have the benefit of training in counterinsurgency tactics at the National Training Center at Fort Irwin, Calif., which has been outfitted to simulate conditions in Iraq for units that are heading there on yearlong tours.
Sen. Patty Murray, D-Wash., said Monday she is concerned about the "less-than-ideal training situation" for the 4th Stryker Brigade of the 2nd Infantry Division, which is based in her state and is one of the two brigades that did its final training at home. That brigade is to go to Iraq in April, one month earlier than planned.
The other is the 2nd Brigade of the 3rd Infantry Division, based at Fort Stewart, Ga., which is due to go in May for its third combat tour since the war began in 2003. Instead of going to the National Training Center first, it imported personnel and equipment — even Toyota pickups like those used by Iraqi insurgents — from the training center at Fort Irwin for two weeks of final rehearsals that begin Wednesday.
A spokesman for the brigade, Lt. Col. Randy Martin, said the soldiers lose nothing by the switch, while shaving about two weeks off their pre-deployment training schedule.
"It's realistic training," he said. "I don't think that anyone would say readiness is affected" negatively. He noted that another brigade from his division underwent similar home-station training before it deployed in January.
"The preferred method is to have them come here," a spokesman at the National Training Center, John Wagstaffe, said in a telephone interview Monday. The main things that cannot be replicated in a home station exercise are the vast spaces of the National Training Center, which is located in the Mojave Desert, and the weather and other environmental conditions that so closely resemble much of Iraq, Wagstaffe said.
"Your weapon won't jam from sand at Fort Stewart," he said.
Murray said she does not doubt the ability of soldiers to adapt.
"They have done everything we have asked of them," she said. "However, I am deeply troubled by the president's escalation plan and am committed to questioning the new demands it places on service members."
On a visit to the brigade's home station at Fort Lewis last week, Murray asked the top commander there, Lt. Gen. James Dubik, whether the soldiers' preparation for Iraq was adequate without going to the National Training Center, according to a Fort Lewis spokesman, Lt. Col. Dan Williams, who said he attended Dubik's meeting with Murray.
Dubik assured her it was, William said. The general told her he was confident "that they were ready to go" to Iraq even if they had not had 1,300 soldiers imported from the Joint Readiness Training Center at Fort Polk to play the role of Iraqi insurgents and civilians and to observe and control the mission rehearsal exercise.
"They went through all the things they know they're going to do in Iraq," Williams said.
Some outside observers say it was inevitable that, in a pinch, the Army would tinker with training.
"It tracks with what we should expect when we hurry the units up in their last three months" before a deployment, said Kevin Ryan, a retired brigadier general and former Army planner who is now at Harvard University's Belfer Center for Science and International Affairs. Army commanders are compelled to make "economies," he added, when an accelerated deployment plan forces them to compress some aspects of training.
Ryan said he doubts this approach will significantly detract from the soldiers' degree of preparation for Iraq.
" 'Adequate' is probably a good description of what that training is," he said. "It's not the premier kind of situation that commanders would prefer, but it is adequate."
Daniel Goure, a military analyst at the Lexington Institute, a think tank, said, "This shouldn't have a decisive impact, although it carries a modicum of risk."
The two units that are skipping their National Training Center sessions are among five Army brigades that are being dispatched to Baghdad on an sped-up schedule as the centerpiece of President Bush's new approach to stabilizing Iraq.
The first to go, in January, was an 82nd Airborne brigade specially designated for short-notice deployments; it did no full-scale final exercise before deploying to Kuwait and then into Iraq.
The next two, from Fort Benning, Ga., and Fort Riley, Kan., did their final training sessions at the National Training Center. The unit from Fort Riley is entering Iraq now and the other is due to arrive in March.