TOHONO O’ODHAM NATION — The first fence to slice through the Tohono O’odham Nation was simple barbed wire meant to keep cows from roaming south into Mexico. The second, which rose nearly a century later, was a sturdier steel barricade that stopped smuggler trucks from barreling north into the United States.

The binational tribe, whose land stretches from Arizona into the Mexican state of Sonora, has long been caught in the middle of disputes over a border between two countries that did not exist when the O’odham’s ancestors first settled here thousands of years ago.

The tribe’s leaders have adapted, working with the U.S. government as it has ratcheted up immigration security on their territory. But now they are facing the biggest wall yet, and they are drawing a line.

The Trump administration wants to build a towering 62-mile barrier that would bisect the Tohono O’odham homeland along the international boundary with Mexico, and construction could begin as soon as next month. Leaders of the Native American nation say it will restrict member movement, endanger wildlife, destroy sacred burial sites and undermine tribal sovereignty while doing little to tamp down illegal activity.

“It’s like me bulldozing right through the Arlington Cemetery,” said Verlon Jose, the chair of the Tohono O’odham Nation. “We don’t matter to the U.S. government. They want to erase us. They want to take our land; they want to desecrate it. They want to hit us where it hurts.”

The tribe has sued to prevent construction, but the federal government is pushing ahead as it seeks to wall off most of the southern frontier. Last month, masked and armed Border Patrol agents escorted a group of contractors through the reservation to do survey work at the planned wall site. O’odham leaders accused the workers of trespassing.

An uneasy cooperation

It is one of many battles simmering along the southern border, where President Donald Trump’s wall has drawn bipartisan outrage in national parks, on private ranches and among environmentalists and Catholic priests. But this escalating confrontation on Native land southwest of Tucson, Ariz., stands out because it upends decades of uneasy cooperation between the tribe and the United States.

The Tohono O’odham Nation, which occupies a reservation roughly the size of Connecticut, has for years allowed federal immigration authorities to operate bases and surveillance towers on its land. The tribe spends $3 million a year on border security, and its police force works closely with Border Patrol agents.

“We’ve bent over backwards to work with the federal government,” Jose said. “But we will never agree to a wall.”

During Trump’s first term, the tribe successfully lobbied against a wall. But since Trump’s reelection, O’odham leaders say they have found federal officials unwilling to compromise.

The administration, which has waived environmental reviews to speed wall construction, has argued that the tribe’s vast and varied territory is a hot spot for cartel-sponsored crime.

“The project will close one of the most dangerous smuggling and trafficking corridors on the Southwest border,” Rodney Scott, the U.S. Customs and Border Protection commissioner, said in a statement.

Illegal immigration and drug smuggling through the reservation surged in the 1990s, raising fears among tribal members and prompting O’odham leaders to increase collaboration with Border Patrol.

“We’ve been homeland security,” Jose said. “We care about who’s coming through our borders.”

The tribe now says the federal government has betrayed that partnership. If the CBP proceeds, Jose said the O’odham could seek to cancel leases allowing the agency’s offices and towers on the reservation.

The tribe sued in June, claiming the wall would illegally reduce the size of its reservation without congressional approval. Its lawyers asked for an emergency court order to stop construction. Last month, a federal judge denied the request, writing that the government’s security needs outweighed the O’odham’s concerns. The tribe is appealing.

Critical to the court challenge is a 60-foot-wide ribbon of federal land that runs along the border from California to New Mexico, known as the Roosevelt Reservation, where the Trump administration has claimed broad authority to build walls.

The tribe argues that its borderland is exempt from the Roosevelt Reservation and that wall construction would inevitably spill beyond the strip.