THE BURNED OVER DISTRICT

Not the United States, yet. The Tohono O’odham tribe living along both sides of the US-Mexican border stands threatened with division if The Tangerine Shitgibbon's Marvelous Fantastic Fence were to ever get built. And they don't like it one bit.

A wall would not just split the tribe’s traditional lands in the United States and Mexico, members say. It would threaten an ancestral connection that has endured even as barriers, gates, cameras and Border Patrol agents have become a part of the landscape.

“Our roots are here,” Richard Saunders said, standing by a border gate in San Miguel, which he and his wife pass through — when it is open — to visit her grandparents’ graves, 500 yards into Mexico. “Our roots are there, too, on the south side of this gate.”

The Tohono O’odham — they call themselves “desert people” — have been around since “time immemorial,” Mr. Jose likes to say; they and their predecessors were nomads in the region for thousands of years, roaming for water and food on mountains and lowlands.

After the Mexican-American War and then the Gadsden Purchase in 1854 delineated the border for good, most of the tribe’s land was left in present-day Arizona, where it still controls 2.8 million acres — a territory about the size of Connecticut — while a smaller piece became part of what is now the Mexican state of Sonora.

The tribe has 34,000 enrolled members, according to its chairman, Edward D. Manuel. Half live on the reservation in Arizona, 2,000 are in Mexico and the rest left for places where job prospects were better. Those who have stayed might work for the tribal government, its Desert Diamond Casino, the schools or businesses like the Desert Rain Cafe, which serves chicken glazed in prickly pear and smoothies made from saguaro fruit, on Main Street in Sells, the reservation’s largest community.

The Tohono O’odham (pronounced Toh-HO-noh AW-tham) reservation has been a popular crossing point for unauthorized migrants and one of the busiest drug-smuggling corridors along the southern border, in part because the federal government strengthened the security at other spots. While a 20-foot-tall steel fence lines the border in San Luis, Ariz., to the west, and Nogales, Ariz., to the east, here the border is a lot more permeable, guarded by bollards and Normandy barriers measuring eight feet, maybe, and, in some areas, sinking in the eroding ground.

Tohono O’odham leaders acknowledged that they were straddling a bona fide national security concern. The tribe reluctantly complied when the federal government moved to replace an old barbed-wire fence with sturdier barriers that were designed to stop vehicles ferrying drugs from Mexico. It ceded five acres so the Border Patrol could build a base with dormitories for its agents and space to temporarily detain migrants. It has worked with the Border Patrol; hardly a day goes by without a resident or tribal police officer calling in a smuggler spotted going by or a migrant in distress, said Mr. Saunders, the director of public safety.

The tribe regularly treats sick migrants at its hospital and paid $2,500 on average for the autopsies of bodies of migrants found dead on its land, mostly from dehydration. (There were 85 last year, Mr. Saunders said.)

The problems faced along this stretch of border illuminate the paucity of thought given to the idea of a wall, if it was ever a real idea. So far it stands as a crude but effective lure for the uninformed.