Arivaca is a town with a difference. While most of America backs the White House announcement last week to curb surging numbers of migrants crossing the US-Mexican border, many residents of this dusty, former gold-prospecting town 10 miles north of Mexico have chosen a different foe: the Border Patrol.

Theirs is an odd counterpoint to the political drive to tighten the border against impoverished migrants – overwhelmingly women and children – from Latin America. But Arivaca's stand has become a beacon for more progressive policies in what has become a complex but defining voter issue.

The Border Patrol, townsfolk claim, has become an interior police force operating outside legal authority which subjects migrants to racial profiling and unlawful searches. Flush with a $30bn boost in Washington-authorised spending, the agency is planning to double the number of border agents to 39,000 – hypothetically enough to place one every 100 yards along the entire 1,900-mile US-Mexico border.

"This is the face of militarisation," says Peter Ragan of the Arivaca group People Helping People, gesturing toward a Border Patrol checkpoint well inside US territory. "Searches are done to intimidate and harass. They can assert control at any time. There's no accountability, no transparency and no oversight."

Protesters say that the agency, which gets more funding than the FBI, Secret Service, DEA and Bureau of Alcohol, Tobacco, Firearms and Explosives combined, is now an important customer for contractors previously focused on supplying drones and sensing equipment for use in foreign military deployments.

They claim that the "border surge" has not only led to the erosion of civil liberties, a decline in tourism and diminishing property values, but that it has forced migrants to trek through remote and dangerous desert areas. Even as overall number of migrants has fallen, figures show, deaths from dehydration and exposure remain constant.

At night in Arivaca, there's a near constant Border Patrol presence, searching for migrants moving under cover of darkness. "Our lives have changed. We have less freedom," says protester Carlotta Wray. "We see helicopters. Border Patrol on the road everywhere. We travel, we get checked." In one encounter a border agent allegedly told a local man: "You have no rights. You're a suspect because you live here."

According to Border Patrol, the Arivaca checkpoint is part of a multi-tiered defence that is successfully reducing the flow of migrants and drugs into the US. "Most cars don't spend more than 10 seconds there," says Border Patrol spokesman Andy Adame. "They ask your citizenship and then you're on your way."

But the political complexity of US border enforcement is exacerbated by allegations of excessive force. A report leaked to the LA Times found there were 67 shooting incidents involving border patrol agents between January 2010 and October 2012, resulting in 19 deaths. By the agency's count, they have responded with deadly force 43 times, causing 10 deaths, most of them unarmed migrants.

One of those killed was a 16-year-old high school student who was shot and killed across the border in Nogales in 2012.

Civil liberties groups accuse the agency of a "shoot-to-kill" policy. Rapid expansion, say critics, has led to poor training and a bullying culture. In one lawsuit a Border Patrol agent in Chula Vista, California, is accused of leaping on the bonnet of a car driven by an unarmed mother of five and shooting her. In another, a customs officer in Texas is accused of violently pushing a disabled woman to the ground. She subsequently suffered a miscarriage.

To many townsfolk, it is the Border Patrol, not Mexican drug smugglers, who have made life worse. It claims increased Border Patrol presence has led cartels to transform into paramilitaries. Increased security on the US side has forced the prices of guides – coyotes – and smugglers up, which plays into the hands of the Mexican gangs.

In some respects the Arivaca revolt is rooted in US identity politics. In the 60s the area was known as a refuge from the draft. Hippies and peaceniks hid out in California Gulch, a fertile valley nearby.

Settler Ken Buchanan says an anti-authoritarian streak is ingrained in the town. Like any border region, smuggling is part of life, he says. In the past, residents would go to Mexico for dinner or dentistry, no passport needed, no questions asked. That era has passed. Last month the American Civil Liberties Union lodged a complaint on his behalf over unwarranted stops at the Arivaca checkpoint. "If they can take my rights away, they'll take away yours," he says. "They have a good excuse to take mine – I live in an area known for drug smuggling – but what happens next? They'll do anything they want if you let 'em."

The issue is attracting film-makers. Lilly Hartley, producer of Who is Dayani Cristal?, a documentary that traces the journey of a missing Honduran migrant whose bones were found near here, says such costs of migration, which should be at "the forefront of our nation's consciousness", are rarely recognised.

But the political dimension continues to grow in importance. The recent electoral defeat of powerful Republican Eric Cantor in West Virginia is credited to his perceived support for an immigration "amnesty".

In Arizona, border agents say the agency is committed to stepping up enforcement. "Even five years ago, the area was out of control," says Adame. "There were aliens running everywhere. Property was getting wrecked. Go out there now and we have a lot more control than we've ever had. If we remove the checkpoints, the criminal gangs will come straight back."

But that doesn't impress members of People Helping People. They accuse the agency of abusive treatment that contributes to the death and suffering of migrants. "It's just constant harassment, with no results," says Ragan. © Guardian News and Media 2014