DOUGLAS, Ariz. — Four years ago, President Trump took office with a pledge to build a towering wall on America’s border with Mexico — a symbol of his determination to halt immigration from countries to the south and build a barrier that would long outlast him.
President-elect Joseph R. Biden Jr. has said he hopes to halt construction of the border wall, but the outgoing administration is rushing to complete as much wall as possible in its last weeks in power, dynamiting through some of the border’s most forbidding terrain.
The breakneck pace at which construction is continuing all but assures that the wall, whatever Mr. Biden decides to do, is here to stay for the foreseeable future, establishing a contentious legacy for Mr. Trump in places that were crucial to his defeat.
In southeastern Arizona, the continuing political divisiveness around the president’s signature construction project has pitted rancher against rancher and neighbor against neighbor in a state that a Democratic presidential candidate narrowly carried for the first time in decades.
The region is emerging as one of the Trump administration’s last centers of wall building as blasting crews feverishly tear through the remote Peloncillo Mountains, where ocelots and bighorn sheep roam through woodlands of cottonwoods and sycamores.
“Wildlife corridors, the archaeology and history, that’s all being blasted to oblivion or destroyed already,” said Bill McDonald, 68, a fifth-generation cattleman and former lifelong Republican who voted for Mr. Biden. “Tragedy is the word I use to describe it.”
Even those like Mr. McDonald who loathe the wall are bracing for the possibility that it could endure for decades to come, basing their assessments on signals from Mr. Biden’s transition team.
While the president-elect has said he will halt new wall construction, other immigration priorities like ending travel bans, accepting more refugees and easing asylum restrictions are eclipsing calls to tear down portions of the wall that already exist.
Advisers involved with the transition team, who spoke on the condition of anonymity to discuss planning for the incoming administration, rejected the notion that there would be any attempt to dismantle the existing border wall, with one adviser calling the wall a “distraction.”
Customs and Border Protection officials are still rushing to meet Mr. Trump’s mandate of 450 miles of new wall construction during his term, nearly doubling the rate of construction since the start of the year. The administration had built 402 miles of wall as of Nov. 13.
Of that, about 25 miles had no barrier before Mr. Trump took office. The rest replaced much smaller, dilapidated sections of wall, or sections that had only vehicle barriers, which border officials say did not deter migrants crossing on foot.
Some of the costliest and most invasive construction is unfolding this month in Guadalupe Canyon, an oasis-like habitat for rare species of birds like the buff-collared nightjar and tropical kingbird.
Until the blasting crews showed up this year, the canyon was so remote — about 30 miles outside of Douglas, the closest town, on largely dirt roads — that ranchers in the area say illegal crossings by migrants were extraordinarily infrequent.
Now parts of the canyon resemble an open-air mining operation. Work crews are blasting cliff sides on a daily basis to build the wall and access roads to it in one of the costliest portions of construction anywhere on the border.
Jay Field, a spokesman for the Army Corps of Engineers, cited the canyon’s “4.7 miles of challenging, rugged and steep terrain” in a statement explaining that the cost per mile for this segment is about $41 million, roughly double the border wall’s estimated average cost per mile laid out in a 2020 C.B.P. status report.
“This isn’t just heartbreaking but totally pointless,” said Diana Hadley, a historian whose family’s ranch includes much of Guadalupe Canyon. She said natural barriers had long served as a deterrent against crossings in the remote area.
Such critical views of the wall are far from unanimous along this part of the border. One prominent supporter of the wall is the Republican mayor of Douglas, Donald Huish, whose family migrated to the United States from Mexico after the Mexican Revolution.
“Once the government does something this big it’s very hard for them to take it back,” said Mr. Huish, adding that he believed that the wall had made the town safer by pushing migrants to cross the border in stretches of desert relatively far from Douglas.
“We’d reached the saturation point of finding illegal aliens in our back alleys, and now that situation has changed,” Mr. Huish said, citing the impact of both the wall construction now underway and portions of the wall that were built before Mr. Trump took office.
Another outspoken wall supporter is Belva Klump, 83, whose family has ranched in Arizona’s borderlands for generations.
“All I can say about the wall is that I’d like to see more of it,” Ms. Klump said. When asked to expand on what she meant, Ms. Klump used a slur to refer to people who cross the border with Mexico without authorization.
“That’s what the wall is good for,” she said.
One of her grandsons, Timmothy Klump, 31, put it another way.
“The wall is a common-sense thing that improves our security and keeps my cows from wandering into Mexico,” Mr. Klump said. “The ranchers opposed to the wall are in the minority.”
In their remaining time in office, Trump administration officials are promoting the wall while criticizing Mr. Biden’s immigration proposals.
Mark Morgan, the acting commissioner of Customs and Border Protection, has said the wall allows the agency to funnel migration into certain areas and strategically deploy agents in places where they can make apprehensions.
Mr. Morgan said Mr. Biden’s plan to stop construction of the border wall was “going to have a dramatic negative impact.”
“This is nothing but politics,” Mr. Morgan said of the continuing controversy over the wall. “It’s really unfortunate and in fact quite disgusting that our ability to protect the American people is going to be negatively impacted because of politics.”
The border agency has thus far concentrated construction in areas owned by the federal government, much of it in areas with terrain that already impedes migration, such as some of the stretches of border in Arizona where work crews are blasting. The government has accelerated construction in some of these places by waiving dozens of laws, including measures protecting Native American burial sites and endangered species.
Rodney Scott, chief of the Border Patrol, said last month that the Rio Grande Valley in Texas, an area with historically high illegal crossings, was a higher priority for the agency. But the construction there has been slow going because the planned path for the wall runs through privately owned land.
While few miles of border wall have been constructed in South Texas, it has had immense impact on landowners there. The administration has filed more than 117 lawsuits against landowners this year to survey, seize or potentially begin construction on property, an increase from 27 lawsuits filed in 2019, according to the Texas Civil Rights Project.
Richard Drawe, a 70-year-old landowner in the area near Progreso, Texas, voluntarily signed over his land to the administration to avoid facing the government in court, conceding that the administration could eventually use its eminent domain authority to take the land anyway.
A year ago, the wall was just a looming presence in the distance. The steel bollards now stretch past his home, cutting him and his wife off from the sunsets and the roseate spoonbills they loved to watch.
“I’m used to living out in the open, no fences, doing what I want to do,” Mr. Drawe said. “I don’t want to see a damn wall when I step out the door.”
But while Mr. Drawe, who voted for Mr. Trump earlier this month, does not want the border wall on his property, he agrees that it will help Border Patrol agents slow illegal migration.
Brian Hastings, the Customs and Border Protection chief for the Rio Grande Valley sector, said the wall has given the agency more flexibility to strategically place agents in areas that lack barriers or surveillance technology.
“We will see the benefits greatly once this wall system is in place without a doubt,” Mr. Hastings said in an interview. “It allows us to be able to respond quicker.”
Still, as construction intensifies, some say it is premature to accept the premise that the wall is here to stay.
Vicki Gaubeca, the director of the Southern Border Communities Coalition, said the next administration could not only halt construction but start taking down some sections, especially those that are harmful to Indigenous traditions or endangered species.
“Look at how destructive the Prohibition era was and how the country moved on,” said Ms. Gaubeca, whose group was part of a coalition that this year won a federal appeals court ruling that the Trump administration did not have the authority to transfer $2.5 billion from the Pentagon for wall construction, sending the matter to the Supreme Court.
“New leaders,” Ms. Gaubeca said, “can pivot away from bad ideas.”
But even if Mr. Biden wants to do so, he could face logistical and financial challenges including the payment of termination fees for canceling some contracts. A single contract in November 2019 for 33 miles of fence replacement in Arizona, currently valued at about $420 million, could cost the government nearly $15 million to terminate, according to ProPublica, which first reported on the fees for altering the contractual agreements.
If the project is halted, border authorities will also likely need to do further work on the river levee where the wall was planned to be built to ensure it is resistant to flooding and approved by the International Boundary and Water Commission, according to Customs and Border Protection. The wall was part of the flood control plan previously approved by the commission, and portions of the levee have already been altered to prepare for the construction of the border wall.
While others seem resigned to living in the wall’s shadow, Karen Hasselbach, who lives on another stretch of the border in Arizona near the San Pedro River, sees things differently.
She said work crews had destroyed the solitude she sought when moving from Maine to the border 23 years ago. Ms. Hasselbach can now gaze at the wall from her front yard.
Ms. Hasselbach said she had begun likening the border wall, which she despises, to the work of Christo, the Bulgarian-born conceptual artist known for epic-scale environmental projects.
“I try to look at it as a temporary art installation,” said Ms. Hasselbach, 69, who owns a thrift store in the town of Palominas. “My hope is it gets torn down.”
Simon Romero reported from Douglas, and Zolan Kanno-Youngs from Washington.