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 departing 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.
Even those 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.