It is 2.45 a.m. and out of the desert shrubland in the cool Arizona night they come. An elderly woman, a girl of around eight, a limping man, a group of young men, 13 in all. They carry water bottles and little knapsacks containing all their worldly goods. They have crossed the border and made it into the promised land, but the promise is already about to be broken. These are the UDAs; the undocumented aliens, the illegals, the "wetbacks". They are about to become another statistic in the border war, a war that has resulted in everything from calls for an invasion of Mexico to accusations of genocide.
This group that has stumbled across the border west of Douglas, Arizona, are some of the 600 or so who will be rounded up by the local border patrol before dawn, a tiny proportion of the 1.6 million apprehended trying to slip across illegally in a single year. Justin Bristow (27) is a New Jersey boy who has been with the Border Patrol for five years. He enjoys the independence of a job that lets him work amid the breathtaking beauty of the sunset over the Mule Mountains. He is one of a growing number of agents brought in from around the country to try to stem the tide.
In the past, the route had taken the migrants mainly through Texas and California, but as those doors have been locked tight in the government's Operation Gatekeeper, they have fanned out to Arizona, with its wide open spaces, its ranches and its negligible political pull. With low unemployment in the US, the constant flow of cheap, compliant non-union labour is vital economically. Many businesses are happy to pay illegals the low rates that few US citizens would accept.
The revenue sent back across the border is vital to Mexico. Its government estimates that $6 billion arrives annually, making it the third largest source of foreign revenue after tourism and oil. There is talk of a "guest-worker" scheme, which would allow people to cross temporarily, of an amnesty to legitimise those who have crossed. There is also talk of a further tightening of patrols.
Douglas is the focus for the crossings. A town of around 18,000 people one mile from the border, its most famous building is the splendid Gadsen Hotel, which boasts a marble staircase with a chip in it supposedly left by Pancho Villa's horse. The Mexicans crossing the border now do not have such a swagger in their step. The group of 13 have been spotted by one of Bristow's colleagues sitting in a "skytower", who is directing torch-wielding agents on the ground.
Two members of the group have made a break for the border. These may be the "coyotes" - the guides who have charged each of the group around $1,000 for the crossing. It has gone up from $600 in a year: an indication, says Bristow, that the increased Border Patrol presence - from 35 agents 10 years ago to more than 500 now - is paying off.
Like the other agents, Bristow uses "sign-cutting", an old Native American tracking skill, to find those who have slipped through. Last year, 1,579,010 people were caught trying to cross from Mexico (by comparison, only 11,660 tried to make it across from Canada).
Those captured squat silent and resigned in the headlights of two Border Patrol vehicles, waiting to be processed, to be offered the chance of a "voluntary return" or to claim political asylum. While the vast majority are Mexicans, there are also Salvadorans, Guatemalans, even Russians, Indians, Iraqis and Chinese.
Many are not aware of the risks. According to US figures, more than 700 people have died trying to make the crossing in the past three years, from dehydration in the desert heat, hypothermia in the mountains, or drowning in the rivers. Immigrant groups say the figure is higher: around one a day.
Back at headquarters in the middle of the night, around 60 people are giving their details quietly to the Spanish-speaking agents. The agents sit behind a screen put up to protect them from the possibility of TB infection. They are questioned, fingerprinted and photographed, then placed on a bus for return to Agua Prieta, just across the border.
Many of those caught have made the attempt many times and will do so again, but unless they seek asylum, they will simply be returned to Mexico. The persistent ones may eventually be charged. "Ten is the magic number," says Bristow.
While he and his mostly young colleagues are the official border protection force, it is the provisionals who have been attracting attention. An hour's drive along the border from Douglas, past the Miracle Valley Bible College and the billboards that urge "Stop the invasion, enforce the law", is Roger Barnett's towing and propane business. Barnett is a legendary character here, not least because he was said to be offering tourists a chance to come and round up the UDAs, a weekend jolly where you could hunt humans.
"Jeez, a person could get rich that way," says the clean-cut Barnett, coming out of his office where antlers on the wall indicate an interest in a more conventional form of hunting. He denies offering such tours, although he agrees that he has charged journalists $1,000 to go hunting with him. And he admits that he goes out most weekends with his guns and his family to round up those who have made it over the fence. "I turn them over to the Border Patrol," he says.
"A lot of people say that the United States needs to invade Mexico. I think that's a hell of an idea. There's a lot of mines and great beaches there, there's farming and resources. Think of what the US could do there - gee whizz, they wouldn't have to come up here any more." There is word in Douglas that the Ku Klux Klan had offered Barnett their help in rounding up the illegals. "Just a rumour. I don't need 'em."
So what does he feel about the people who try to cross the line? "It's upsetting. I feel sympathy for them . . . that country is run by a third-world narco-dictatorship."
HE is not bothered that the US justice department may investigate his hunting activities: "Let 'em come. It's a shame our government can't take care of its own people." As for the Mexicans who have offered a $10,000 bounty on his head and those of other ranchers who run the round-ups: "Let them come, too."
Back in Douglas, Larry Vance Jr, whose father was a Mexican immigrant, is the chairman of the Cochise County Concerned Citizens, founded in 1999 to "restore and preserve our sovereignty". He would like to see US troops and tanks deployed on the border and thinks that if this is not done American citizens will seek their own solution.
"What is going on is an act of war against the United States and an act of genocide against their own people," Vance says of the role Mexico is playing. "My dad was a Mexican immigrant - legal - and I have friends and family in Mexico. They tell me that people are being told, `Get past the first 30 kilometres and you've got a goldmine - jobs, medicine, education for your children and citizenship if you stay long enough.' "
He likens the illegal immigrants to the wildebeest streaming across the African plains. "All the predators go for them. There are rapes and robberies and beatings outside my house all the time." He foresees a shooting war on the border. "Where a native population has been diluted by invaders it runs into a bloodbath. We abhor violence but we realise that people have the God-given right to defend themselves."
Others in Douglas have a less apocalyptic view. At a Rotary Club luncheon at El Alamo restaurant, Cindy Hayostek, a local reporter who has seen would-be immigrants piled "like firewood" in the back of their coyotes' vehicles, says: "We know they are living in abject poverty and subjecting themselves to modern-day slavery".
"It's sad," says businessman Nick Arreola. "You see them sometimes on the road when their coyote hasn't shown up and they've run out of water. They're just waiting to be saved."
Walk half-a-mile from Douglas into Agua Prieta in Mexico and the contrasts are stark. The ill-stocked shops have hand-painted signs, the cars are old and battered and children hustle for quarters. It is here that many people come as they prepare for their leap of faith across the border. And what lies beyond the fence is enticing: "Go bananas at Dairy Queen," cajoles the first shiny billboard across the border.
"We didn't cross the border, the border crossed us," is the much-used remark by Mexicans who have made it over the border. To an extent this is true: the settlement of the Mexican-American war of 1846-48 meant that, for the sum of $18,250,000, the whole of California, most of Arizona and New Mexico and parts of Utah, Nevada, Colorado and Wyoming passed to the US.
All of which is academic for people like Jose, who was caught four times before he finally made it over the mountains. "We were frightened before we came across because breaking the law was against our culture and we were all crying because we had been told that they (the Border Patrol) were very mean. But they were very nice - they gave us lunch, we were in jail for the night and then we were taken back over the border and they said to us, "Good luck next time!' "
Jose said that he had come over because it was impossible to live on the $35 a week he earned in Mexico. "But it was very hard to leave our family and our town - I was crying every day for two weeks after I came over." The coyotes were "very mean - my brother-in-law came in with a woman who had a heart attack and the coyote said, "Leave her there, let her die.' "
Miguel has made the crossing three times, on the last occasion paying $700 as a down payment and the rest on safe arrival at his destination. Of the coyotes, he says: "They don't respect you as people. If you break a leg, they leave you there. It's a person you are paying for a service and sometimes they treat you badly, sometimes well."
He would often have to wait for around a week in a Mexican border town, waiting to be told the right moment to make the crossing, sometimes in groups of up to 20 with two smugglers guiding them.
Both George W. Bush and Al Gore refused Barnett's invitation to visit. Neither presidential candidate, desperately seeking the Latino vote in Florida and California, is going to be saying much about the border until after the election. But the Border Patrol, the ranchers, the coyotes and the bewildered souls kneeling in the headlights must all know that the border war cannot be fought like this for ever.