Verlon Jose knew nothing of borders until he was a teenager.
The native American's grandparents had a summer ranch in the hills of Arizona and a winter ranch a few miles south, in Mexico’s state of Sonora. But to him the difference was purely academic: he and his family would travel freely across the tribal lands their ancestors had lived on for thousands of years.
So when a president was elected on a promise to build “a big, beautiful wall” right across the heart of the Tohono O’Odham reservation, a line in the sand was drawn.
“This could be the last of the Indian Wars,” the 50-year-old vice chairman of the 34,000-strong Tohono nation, said as he warned President Donald Trump of an Indian uprising.
The 21 tribes of Arizona – the Tohono O’odham is the second largest in the US after the Navajo, with a reserve the size of Connecticut – have said they will come to their aid. All 567 tribes that make up the National Congress of American Indians have pledged to do whatever it takes to stop the 30ft barrier severing the ancient reservation in two.
“The tribal leaders said you call us, and we’ll come. You lay one brick, they said, and we’ll come.”
Since October eight wall prototypes have been standing in San Diego, and in late November border patrol officials began “stress testing” the structures with shovels, saws, grappling irons, jackhammers and ropes.
Agents were photographed hurling themselves at the walls, trying to heave themselves up, over and across.
A decision on which wall performed best from the $20 million prototype programme is expected early this year.
The funding for the full 2,000 miles, however, is far more contentious – even despite the fact that Mr Trump appears to now accept some sections of it are impossible to build upon.
On the campaign trail, he said that it could be built for $8-12 billion. The department of homeland security now estimates the construction to cost $21.6 billion, but Senate Democrats put the total at more than three times that – nearly $70 billion, with an additional $150m a year in maintenance.
If it does go ahead it will cut off the 2,000 Tohono native Americans on the Sonoran side from their kinsmen in the north.
“I say, in the spirit of my elders, over my dead body,” Mr Jose said.
Some traditional ceremonies of his Tohono O’odham Nation took place in Sonora, and some in Arizona; some graves of family elders had to be visited in Sonora, and some in Arizona. The land was under the control of Mexico until the 1853 Gadsden Purchase, when it was handed over to the United States. But the white border markers erected then, which still stand today, meant little.
“There was no border. It was just our home,” said Mr Jose.
As the decades passed he watched as divisions were created. Little by little fences went up; today the 62 miles of US-Mexico border inside his tribe’s reservation is marked by a series of metal bollards designed to stop cars, and a line of welded metal rails
“It’s already a scar on our people," he added.
“I can’t imagine waking up and seeing a wall here. I would die. This is already a line across my heart. And this sentiment has been echoed by many others in my community.”
Back on the border, less than 50 metres from the rails, on the Mexican side, a young couple in camouflage clothing is trekking through the mesquite shrubs; the girl, who gives her age as 15, evidently pregnant.
“We’re just going for a walk,” they reply, asked where they are heading.
Richard Saunders, director of the Nation’s department of public security, laughed. His 90 police officers patrol the 77 villages in the Nation; this year alone they have found 43 dead migrants in abandon houses and among the undergrowth.
“There is not one community that isn’t impacted by the border, in one way or other,” he said. “It could be smugglers passing through with backpacks full of drugs. Or illegal aliens. It could be the border patrol circulating. Ranchers finding their fences cut. People sheltering the illegals, for money, or getting involved in the smuggling themselves.”
And yet, living and breathing the border, wanting to keep his community safe, he thinks the proposed wall is nonsensical.
“And I don’t think it will be built,” he said. “Maybe a bit in California or Texas. But here? The geography is impossible, and there’s just too much opposition.”
The president is unperturbed: at a rally in Phoenix, Arizona in August he said he would shut down the government if his border wall budget was not passed.
"Believe me, if we have to close down our government, we're building that wall,” he said, appearing now to have forgotten his vow that Mexico will pay for it.
“The American people voted for immigration control. That's one of the reasons I'm here, and that is what the American people deserve, and they're going to get it.”
Yet while Washington politicians wrangle over the plan, the government employees on the ground are getting on with the job at hand.
Customs and Border Patrol (CBP) is the largest of all federal agencies, employing 60,000 people. The border patrol, a division of CBP, currently has just under 20,000 agents and is on a hiring spree, following Mr Trump’s January 25 executive order requiring the recruitment of an additional 5,000 agents. The consulting firm Accenture has been brought in to help, at a cost of $297 million – almost $40,000 per recruit.
On an average day, the CBP forces will seize 7,900lbs of drugs and stop 1,140 people illegally crossing the border. Yet the number of detentions is plummeting: at the beginning of December it hit a 45 year low, with 304,000 along the Mexican border. Critics say that shows a border wall is not necessary.
Daniel Hernandez is a 36-year-old border patrol agent working from the Tucson sector – the largest in the country, with a region that encompasses the four million square miles of the Tohono reserve. He says relations with the members of the Nation are good. Tribal people must respect federal law but have their own jurisdiction for state-level matters.
“We work together,” he said. “It’s a relationship of mutual respect. And they don’t want to see drug smugglers walking through their land, recruiting their young people, any more than we do.”
Stephanie Dixon, 30, is one of the few female border patrol agents – currently they make up only five per cent of the force. The ten hour shifts, alone, in remote and inhospitable territory, makes it a tough job for anyone. For two and a half years she patrolled on horseback.
"I just do my thing," she said.
“There’s a lot of talk about the wall, of course,” said Mr Hernandez. “But it’s not a one-size-fits all policy. It has to be used strategically. At times it’s better to have more patrols, perhaps, or use the latest technology.”
Asked what would make his life easier, and he replies improved technology – telling how, in his early days on the force, they used seismic detectors to find illegal entrants, and then spent hours hunting for what turned out to be a couple of cows. Now infrared technology, helicopters and high-resolution imagery from watchtowers is key.
A seven-year veteran of the force, he is passionate about treading as lightly as possible along the border and shakes his head when asked if he’d like to see a Hadrian’s Wall type system of fortresses.
“We don’t want a life-altering experience at the border. We want the least intrusion possible – if we could have a virtual wall, I’d take that. We don’t want people to wake up and see the landscape changed forever.”
Back on the border, his colleagues drive slowly through the Nation, rocking and rolling in white pickup trucks across sandy trails. Further to the west the border becomes vertiginous mountains; Mr Jose chuckled at the thought of attempting to build a wall there.
In yet another section the Vamori Wash flows – it is dry now, but come the summer rains it becomes a surging, impassable torrent deeper than the roofs of the 4x4 patrol cars. Mr Jose tells how attempts to build even a bridge over it failed; three feet below ground it becomes water. A border wall would be impossible.
Mr Jose will not say what legal measures the tribe are preparing – he laughs, saying that, like Mr Trump, he prefers to keep his strategy silent.
Bernard Siquieros, a 68-year-old elder of the community and curator of the local museum, speaks sadly of the impact that the increase in border barriers have had. It was 9/11, he said, that sparked the instillation of the vehicle-proof border; before that it was just three strings of barbed wire.
“Putting fences across a land where there were no fences has had a big impact,” he said. “Our ancestors come from Green Well, on the other side of the border. So even now we are separated, divided.”
Asked if he thinks the border wall will be built, he replies: “I hope not. It’s a big waste of money. And a president only interested in his own vanity project.”
He tells how the Nation see themselves as custodians of the land, and will fight to preserve the migration paths for their wildlife and the natural environment around the border.
Mr Jose agrees, adding that, in addition to being expensive and insulting, it’s simply unworkable.
“The Great Wall of China. The Berlin Wall. Tell me if they have been successful? Research tells me that they have not. They were torn down. So why would we want to spend $30-$60 billion of taxpayers’ money on something that would not be effective?
“I’m making a plea to Donald Trump: come, and walk the 62 miles with me. Then you will see why this is such a bad idea.”