Helen Ramajo, 11 years old, reached the U.S.-Mexico border before the American presidents did.

As President Biden and former President Donald J. Trump prepared for the political stagecraft of dueling visits to two Texas border towns, Helen slipped through a gap in the wall in southern Arizona on Tuesday morning, her fuzzy bear-eared hoodie pulled up against the chill.

“A dream!” she said. She, her father and older sister left Guatemala a month ago, and they now trudged toward a makeshift camp with other tired, dehydrated migrants to wait beside the wall to surrender to U.S. immigration authorities.

Illegal crossings across the Southern border have plummeted in the last month, but even a slow day means dozens of migrants arriving every few hours, a ritual that has come to define life in border towns and nearby cities. Migrant aid workers say they often see around 200 people a day crossing in this area of the border outside the tiny town of Sasabe, southwest of Tucson.

A visit from two presidential candidates seeking to persuade voters they can tackle the border crisis may check an election-year box. But in this corner of southern Arizona, which now has the most undocumented crossings of any stretch of the entire Southern border, ranchers, aid workers and other residents who live and breathe the border crisis said the problem had become too intractable and complicated for any politician to tackle.

“I have no faith that it will ever be solved,” said Lori Lindsay, a cattle rancher whose Tres Bellotas ranch runs along a slice of the border wall.