The lead vehicle in the convoy has disappeared over the hill. The road ahead is flanked by two suspicious-looking car wrecks. In the back of the pick-up truck, the troops are getting twitchy.
All six soldiers jump out of the truck and sprawl in the dirt, triggers at the ready. Minutes later, they clamber back in. Nobody thinks to look behind until a smoke grenade explodes three yards away. The buzzer sounds. "A grenade. We're dead, dude," says Private Tyler Franzen.
They were wiped out within the first five minutes of their drill on convoy movement, and the implications register quickly. Days from now, Pte Franzen and the 319th Signals Battallion could be in Iraq. "This makes me more scared," he says. "I am preparing for the worst."
Their trainer calls troops like these "bullet magnets" - army reservists or National Guard soldiers, weekend warriors with minimal combat training pressed into service.
Tens of thousands are on the move now as the Pentagon carries out the largest rotation of forces in its history, relieving battle-weary soldiers in Iraq, Afghanistan and Kuwait with fresh forces. By late March, 130,000 troops will be leaving Iraq and 105,000, including some of the 319th, will arrive. As many as 50% of these will be reservists or National Guard.
Some units, like the 319th, will be raised virtually from scratch. The signals battalion, based in Sacramento, California, was barely at half-strength when it was mobilised, and reservists have been drafted in from as far away as Puerto Rico, Delaware, and Georgia to be sent off to what the troops call the "sandbox"
They are joining a different war from the one fought by the invading force that set off last year to liberate Iraq from Saddam Hussein. Today, the mission is far less clear, and more dangerous. The original rationale for the invasion - weapons of mass destruction - has been discredited, and so has the notion of a swift military victory. The toll for US forces in Iraq is approaching 550 dead.
A number of officers and troops at Fort Bliss say it is important to draw a line between personal feelings and duty. A few reservists say they have had run-ins with anti-war protesters; they feel the troops are not being supported as they should.
Nobody at Fort Bliss is raring to go off to war, but they are going to honour their obligations. Specialist Michelle Matthis, 21, volunteered to fill vacancies in the 319th once it became clear her own unit would not be deployed. But even she seems somewhat ambivalent. "It's so I can get the war over with," she says.
Others are resigned to going to this war, but they say it will be their last. The cost on family life is just too great, says Jim Akers, 40, a warrant officer. This is his first deployment after 22 years in the reserves.
He knows the Pentagon is worried about a steep drop in re-enlistments in the National Guard and reserves, but after Iraq he will have done his bit. "Even $1,000 extra a month is not going to keep me there," he says. "I will retire when I get back. I am not going to put my family through this - or myself."
By the time the troops have arrived at Fort Bliss in western Texas, they should be all but ready to go. But the fact of their deployment has yet to sink in. "I kind of expected this, but I didn't think it would happen," Pte Franzen says. He signed on for the college benefits in January last year. Two days before basic training, his girlfriend learned she was pregnant. Now he is 19 - too young to drink in Texas - has a three-month-old son, and is days away from war.
The shock of deployment was even greater for veterans like Maritess Leyson, 37, a computer systems administrator from Chicago who describes her 18 years in the army reserves as a "hobby job". When the call came last November, the single parent was in a panic to try to soften the news for her three teenage children. Then she had to find them a home after her sister balked at taking them. "When it was time for me to go, it hit me like a brick wall, oh my goodness," she says. "It's scary, but I signed on the dotted line."
None of the reservists raises the possibility that they might be killed - their instructors do that for them. "If the Iraqis executed an ambush with any degree of efficiency some of you might not come home," says Major Shawn Marshall, after drill.
What he does not need to say is that the death toll in Iraq has been especially high for reservists, National Guard members and support units. There is no frontline in Iraq, and no zone of safety for non-combat forces. Most reservists and support units have not been trained for a guerrilla war - with lethal consequences.
They simply do not know how to fight. Some freeze in training exercises. At the firing range, they blast away, and the targets still stand. They were trained in technical skills, not combat capabilities.
"These people are what I call bullet magnets," says Colonel Rick Phillips, who is in charge of training. "What they find over there is that these kids aren't pulling the trigger. They are waiting to engage."
At Fort Bliss, that knowledge is especially acute. The base was the home of Private Jessica Lynch and the mechanised unit that took heavy losses in the opening days of the war when their truck took a wrong turn near Nasiriya, and drove into an ambush. Eleven soldiers were killed; and others taken prisoner.
Those blunders led the Pentagon to institute basic battleground drills for all forces departing for Iraq. Col Phillips has four days to drill survival instincts into his people. He knows he can not make warriors out of them."I just want to give them enough to help them to come home."www.guardian.co.uk/international/story/0,3604,1159141,00.htmlE-mail this article