The solution favored among ranchers is infused with a fatalism that nothing will change — government being government, and the cartels always one step ahead — so why bother. But here it goes:

Intensive, round-the-clock patrols along the border are required for a fence or wall to work; otherwise, those determined to cross will always find a way. But, they argue, if you have boots on the ground, you will have no need for anything so beautiful as the Great Wall of Trump.

It is easy, from a distance, to dismiss the ranchers along the border as right-wing Chicken Littles whose complaints hint of racism. Too easy, in fact.

Ranchers will say they saw people with backpacks trekking across their property last week, last night, early this morning. Some will say they have grudging agreements of access with drug cartels, as long as trespassers stay far from their homes. Dogs bark, motion lights flicker, things go missing.

The unnerving has become everyday life, Mr. Ashurst says, and then he asks my colleague and me where we live. Metropolitan New York, we answer.

Nice, Mr. Ashurst says, still scowling. “But how would you like it?” he asks, referring to the ebb-and-flow parade of strangers, some armed, past his door. “Do you think you’re more important than the poor moron who has the misfortune to live along the border?”