Granica meksykańsko-amerykańska - NYT

A Border Patrol agent operates a forward-looking infrared camera from a helicopter near McAllen, Texas, May 18, 2017. Surveillance towers, drones, hel...

A Border Patrol agent escorts a man apprehended illegally entering the country near McAllen, Texas, May 18, 2017. Surveillance towers, drones, helicop...

A group of men scatter on foot as a Border Patrol agent tracked them on a private ranch near the border in McAllen, Texas, May 18, 2017. Surveillance...

An aerostat, which can hover as high as 5,000 feet, docked near the Rio Grande in McAllen, Texas, May 17, 2017. Surveillance towers, drones, helicopte...

Refurbished UH-1N Huey helicopters, once operated by the Marine Corps, at a U.S. Customs and Border Protection hangar in McAllen, Texas, May 18, 2017....

Border Patrol agent James Pridgen in the cockpit of a helicopter near McAllen, Texas, May 18, 2017. Surveillance towers, drones, helicopters and unman...

Michael Johnson, a Border Patrol agent, looked out over the Rio Grande from an old dock near Roma, Texas, May 15, 2017. Surveillance towers, drones, h...

Barbed wire strung along the old Roma-Ciudad Miguel Alem?n International Bridge, now closed, in Roma, Texas, May 15, 2017. A new, parallel bridge carr...

United States Customs and Border Protection agents apprehended a man seen crossing the Rio Grande near Roma, Texas, May 15, 2017. Surveillance towers,...

A well-established path through the tall grass along the Rio Grande in Roma, Texas, May 15, 2017. Dense brush along the Rio Grande makes the use of hi...

A Border Patrol agent inspects the interior of an empty semi trailer in Pharr, Texas, May 16, 2017. As vehicles approach checkpoints, stationary camer...

A Volkswagen Passat which was seized with more than $250,000 hidden inside its rear bumper at an inspection station in Hidalgo, Texas, on the border w...

A man sits right by the formal border line on the a bridge between Reynosa, Mexico, and Hidalgo, Texas, May 16, 2017. As vehicles approach checkpoints...

Cameras at the port of entry in Hidalgo, Texas, May 16, 2017. As vehicles approach checkpoints, stationary cameras take images of the front and rear l...

Leo Ibarra and Max inspect a car at the port of entry in Hidalgo, Texas, May 16, 2017. As vehicles approach checkpoints, stationary cameras take image...

Traffic on an approach to the bridge between Ciudad Miguel Alem?n and Roma, Texas, May 15, 2017. This new bridge sits parallel to an old one, now clos...

Dogs bark in a residential area as Border Patrol agents responded to reports of an attempted crossing of the Rio Grande in Roma, Texas, May 15, 2017....

Border Patrol agent Christian Salmon apprehends a Honduran national who crossed the Rio Grande in an inflatable raft near Roma, Texas, May 15, 2017. S...

Border Patrol agent Christian Salmon apprehends a Honduran national who crossed the Rio Grande in an inflatable raft near Roma, Texas, May 15, 2017. S...

Border Patrol agents Michael Johnson, left, and Christian Salmon apprehend a Honduran national who crossed the Rio Grande in an inflatable raft near R...

Jonathan Hoyt, a Border Patrol agent, monitors video surveillance feeds from a shed near the Rio Grande in Roma, Texas, May 15, 2017. Surveillance tow...

A motion-triggered surveillance camera, disguised in a bundle of old clothing in the brush along the banks of the Rio Grande near Roma, Texas, May 15,...