The five-year agreement between U.S. Customs and Border Protection and Anduril Industries calls for the company to deploy hundreds of solar-powered mobile surveillance towers designed to operate in rugged locations. With cameras and thermal imaging, they detect moving objects and feed an artificial-intelligence system capable of distinguishing among animals, humans and vehicles, sending location and mapping information right to the cellphones of U.S. patrol agents.

The effectiveness of the Anduril system in pilot programs so far, and the administration’s deepening commitment to the technology, raises an obvious — if awkward — question for homeland security officials as Trump spends billions of taxpayer dollars to speed up his border wall project. If the Anduril system can spot migrants and smugglers from miles away and guide U.S. agents right to them, what is the point of building a costly physical barrier in isolated border areas where there are few crossings?

In their opposition to Trump’s physical border barrier, many Democrats have promoted “smart” border technology as a more effective and cheaper alternative to the $15 billion concrete-and-steel version Trump is racing to install and which he is promoting on the campaign trail.