Tucson, Arizona – In the Sonoran Desert north of Tucson, Arizona, the telltale signs of migrants heading north are scattered beneath shrubby trees and in dried-out stream beds: empty jugs of water, desiccated backpacks, tattered blankets and faded pieces of clothing.
It’s difficult to say how long ago they were left behind. The harsh elements of the desert accelerate the breakdown of clothes and people.
“The conditions are extreme, during the day and the night,” said Francisco, a 30-year-old from southern Mexico who declined to share his last name. “We ran out of food and water on the third day. We drank out of green pools of water on the ground.”
He says his weeklong trek through the desert ended when his group of five people were apprehended and deported by the United States Border Patrol. Sitting in a corridor on the Mexican side of the border city of Nogales, he says he plans to spend the holidays with his family in Mexico before returning to try his luck again in the new year.
Migrants like Francisco are at the heart of a heated general election unfolding in the US.
Both Democratic candidate Kamala Harris and Republican contender Donald Trump have made tightening immigration a centrepiece of their campaigns in the waning days of the race.
Harris, the current vice president, has pledged additional restrictions on the right to apply for asylum. Meanwhile, Trump, a former president, has announced plans to launch a project of “mass deportation” if he retakes the White House.
Candidates in down-ballot races have echoed their calls for heightened restrictions, too.
But amid the tough talk on the campaign trail, experts say the human cost of such policies is being ignored, often with fatal costs.
Immigration has long been a defining issue in the politics of Arizona, one of four US states that share a border with Mexico.
While calls for immigration crackdowns are easy to find in television advertisements and billboards, the state has also been deeply shaped by its proximity to Mexico. Its connection to Latin America far predates its status as a US state.
At an early voting station in Tucson, residents expressed mixed feelings about immigration and its current place in national and state politics.
“I think that’s a very blown-up issue,” Margaret Wilch, an educator, told Al Jazeera. “I’ve spent a lot of time on the border. I’ve lived here for almost 40 years. I don’t feel overrun by anybody, and I love the diversity and the culture of this community and this state.”
David, a 68-year-old retiree who recently moved to the area from Pennsylvania, says he considers immigration one of the most important issues of the election. He asked to withhold his last name, in order to speak freely.
“Having open borders isn’t good,” David said. “My ancestors, they came over from Italy and Germany. They went through Ellis Island. They had to be vetted. They had to do everything. And now we’re just letting people come in.”
Experts, however, point out that the US does not have an “open border”, as many Republicans claim. If anything, the process of crossing the border has become more restrictive under outgoing President Joe Biden.
Whereas international law requires that asylum seekers be allowed to flee persecution across borders, Biden has sought to limit that right, largely requiring online appointments be made instead.
Those who fail to abide by the policy can face a five-year ban on re-entry and possible criminal charges. But that has left some families in limbo, stuck in dangerous circumstances along the border or other parts of Mexico as they wait to apply for safety in the US.
In Nogales, for instance, a Cuban man holding a two-year-old girl told Al Jazeera he had been waiting in Mexico for six months for an initial appointment to petition for refuge in the US.
But the belief that there are no barriers for people who want to enter the country has been a central part of the Trump campaign, which has leaned into dark, nativist rhetoric that portrays immigrants as criminals and a drain on the country’s resources.
“The day after I take office, the migrant invasion ends,” Trump said on Monday at a rally in Raleigh, North Carolina, where he described migrants as “vicious and bloodthirsty criminals” and promised to “kick them out of the country”.
Research, however, shows that immigrants are less likely to commit violent crimes, and undocumented workers pay taxes that contribute to social programmes that they themselves are unable to access.
In Arizona, a state ballot measure titled Proposition 314 would give state and local authorities a greater role in immigration enforcement, which has traditionally been the responsibility of federal authorities. It would also shield officers in the state from civil lawsuits that allege racial profiling.
A September poll showed that the measure was on track to pass, with 63 percent approval.
“The talk around immigration has gotten a lot more negative,” said Sulma Arias, the director of the organisation People’s Action, which knocks on doors and focuses on in-depth conversations with voters in swing states like Arizona.
“A lot of people are connecting immigration to their own lack of material wellbeing,” she added, noting that false claims about undocumented immigrants voting in elections have also become more widespread. “There’s less talk about the positive contributions of immigrants.”
Experts also warn that the fevered rhetoric around immigration in the unfolding election could worsen a humanitarian crisis at the border and make it easier to justify harsh policies.
Last year, the International Organization for Migration, a United Nations entity, named the journey across the US-Mexico border the “deadliest land route for migrants worldwide on record”.
"There's a lot at stake in terms of how this country wants to live," Father Ray Riding, who volunteers with deportees and asylum seekers, told Al Jazeera. "When you dehumanise people, you can do whatever you want to them."
In order to avoid a web of Border Patrol checkpoints that extend far into the US interior, many migrants spend days walking through remote routes deep in the desert where they are less likely to be apprehended.
After a long journey through Mexico — where migrants routinely face extortion, rape and abuse by law enforcement and criminal groups — the days of trekking through the desert represent a final, lethal test.
“The journey is horrific, and it doesn’t start in the borderlands. For many people, it starts thousands of miles away,” said Dora Rodriguez, a humanitarian worker who nearly died in the desert herself when political violence by a US-backed military government in El Salvador pushed her to flee to the US in the 1980s.
In the area around the Silver Bell Mountains, about 113 kilometres (70 miles) north of the US border with Mexico, there is little respite from the sun. It is at least 87 degrees Fahrenheit — or 30 degrees Celsius — by 11am when volunteers with the humanitarian group No More Deaths set out for their first hike.
They aim to drop off water and supplies at areas known for migrant activity.
The terrain is rocky, uneven and covered in thorny plants capable of wearing out an otherwise sturdy pair of shoes. Along with jugs of water and an assortment of salty, high-calorie foods, the volunteers leave buckets of thick socks.
“Something as mild as a sprained ankle or a blister can be lethal in the desert,” said Kyla Neilan, a volunteer who has worked with No More Deaths for 10 years. “If a migrant can’t keep up with their group, they can get lost or left behind.”
Other problems that would normally pose few serious health risks can also prove deadly. Some migrants get diarrhoea when desperation pushes them to drink from cattle troughs filled with algae — and the condition can lead to further dehydration.
Neilan and others like her are insistent that, while migrant deaths are most often attributable to exposure to the elements, they are a direct result of US border policy.
First outlined in a 1994 Border Patrol planning document, “prevention through deterrence” relied on a simple assumption: that focusing law enforcement resources on urban ports of entry would deter people from crossing. The idea would be that migrants would give up once faced with “hostile terrain, less suited for crossing”.
Though that policy has failed to stop migrants from coming to the US, it has undoubtedly succeeded in making their journey more deadly.
Greg Hess, the Pima County Medical Examiner, told Al Jazeera that it was relatively uncommon to find the bodies of deceased migrants in the desert around Tucson in the 1990s, when border policies first began funnelling migrants into increasingly remote areas.
“We average about 170 [deceased migrant] remains per year if you’re looking from 2002 through 2023,” he said, citing figures for Pima County. “That’s in contrast to less than 20 back in the 1990s.”
Throughout the day, Neilan and two more volunteers drop 48 gallons of water at several points in the desert. They calculate common migrant routes using a combination of geographic mapping and indicators such as locations where bodies have frequently been found.
Faced with brutal elements and scavenging animals like javelinas, vultures and coyotes, bodies often disappear with little trace. Neilan says No More Deaths has volunteer doctors and pictorial guides to help differentiate animal bones from human ones.
By 1:30pm, the heat had risen to 94F, or a sweltering 34C. During the summer, the volunteers say that temperatures of 116F, or 47C, are common.
“We are at risk of heat illness ourselves out in the field, and we’re hiking relatively short distances with frequent breaks back in an air-conditioned truck packed with water,” said Neilan. “Imagine what the risk is like for migrants who have spent days trekking through the desert with little food or water.”
While anti-immigrant sentiment is far from new in the United States, supporters of immigrant rights say they have grown alarmed by its severity in recent years.
“These are tough people. These are people who have been in jail. They’re killers. They’re murderers. The level of viciousness is unexcelled,” Trump said of immigrants at a rally on the final night of his presidential campaign.
Rodriguez, the humanitarian worker, says that she cannot remember a time when the identities and experiences of migrants themselves were so absent from the conversation about immigration.
“I see so much fear now. People hear the word ‘immigrant’, and they think of someone who is going to take their job or rape their daughter,” she said. “The narrative is so far from humanity.”
On a Tuesday afternoon on the Mexican side of Nogales, she greets people recently deported from the United States, easily identifiable by the ziplock bags of possessions they are allowed to keep. Their shoes have no laces: The strings are confiscated by Border Patrol, to prevent people from taking their own lives while in detention.
Rodriguez offers a warm smile, along with socks, drawstring bags and advice about local shelters where they can sleep safely for the night.
As a group of exhausted-looking deportees assess their options on a row of benches, a man plays the Frank Sinatra hit My Way on a battered Yamaha keyboard.
“We should be talking about why people are risking their lives and choosing to leave their communities and loved ones with only a backpack,” said Rodriguez.
“The people trying to come here have a desire to be safe,” she adds. “They are people who have hopes.”