The border fence between the US (on left) and Mexico (on right). | Sgt. 1st Class Gordon Hyde / Wikimedia

Trump’s wall is already there?—?we just can’t see it.

There’s hardly a better symbol for what Donald Trump wants for the US than a wall along the border with Mexico. He knows exactly how to use the prospect of a physical border wall to inspire his racist supporters to a xenophobic frenzy. What he’s leaving out, though, could be just as important: a virtual wall?—?one that’s already in the works.

But a virtual wall sounds less impressive than a physical one in Trump’s chest-thumping, grammar-eschewing rhetoric, so it’s the physical wall that Trump is touting as the solution to stop the flow of people across the U.S.’s southern border?—?people Trump has called “bad hombres” and “rapists.” The wall Trump wants would span nearly 2,000 miles?—?a far cry from the 653 miles of fence currently strung along the border.

The technology for a virtual wall dates back to the 70s, when unattended ground sensors were invented. These sensors, which are essentially devices that transform changes in physical activity into electronic signals, have become more advanced since then. They’re now smaller and solar-powered?—?perfect for hiding in the vast desert expanses between Mexico and the US.

In 2006, under George W. Bush, the government embarked on a project known as the Secure Border Initiative Network, or SBInet. The point of the program was to use networked technology to better secure the US’s border with Mexico.

A rough idea of the SBInet system. |

SBInet was canceled in January 2011 “due to cost overruns and schedule delays,” according to the Department of Homeland Security. Part of the problem was the rugged terrain along the border, which caused problems with data transmission, and bad weather conditions, which sometimes caused the radar to malfunction.

Now, the government is pursuing a new, though familiar, project: the Integrated Fixed Towers program, which the Department of Homeland Security says will “provide automated, persistent wide area surveillance for the detection, tracking, identification, and classification of illegal border incursions between parts of entry.” The system, which has been operational in Nogales, Arizona since 2015, relies on tower-mounted radar and day and night cameras to keep a watchful eye on the border. The cameras beam their feeds to a CPB post, where agents look for signs of movement.

Surveillance atop a tower at the border. | Wikimedia

The Integrated Fixed Towers program is only a part of an array of technologies used at the border. Complementing it are Remote Video Surveillance Systems, which rely on cameras and radio- and microwave transmitters to send video to a control room so an operator can “remotely detect, identify, classify and track targets using the video feed,” according to CBP testimony from May 2016.

There are also technologies free from the constraints of fixed structures. Cameras mounted on telescoping poles on border control trucks provide footage from multiple angles. Meanwhile, Tethered Aerostat Radar Systems (blimps, essentially, that are tied to the ground) provide broad surveillance from above, using long-range radar to detect low-altitude aircraft and other vessels from up to 200 miles away, according to the US Customs and Border Protection (CBP), which says these blimp-like aircraft captured footage of more than 330 suspected border-crossing attempts in fiscal year 2016.

US Customs and Border Protection

Drones, of course, play a part in border security, too, as they seem to play a part in any modern warfare (since that’s what this assault on the border borders on); in fact, part of the reason they’re being used stateside is because of government efforts to reuse extra military equipment. Unmanned aerial vehicles are already used to patrol the border, looking for changes in terrain?—?their sensors are so precise that they can detect something as faint as a footprint.

Last year, Trump made clear that he supports the continued use of drones to surveil the border.

Plenty of taxpayer money goes towards these technologies: In fiscal year 2016, the US Department of Homeland Security budgeted $373.5 million for infrastructure and technology “to ensure law enforcement personnel are supported with effective surveillance technology.”

Gerald L. Nino / Wikimedia

Given that CBP kills more people annually than any other US federal law enforcement agency, giving them more ways to take people down is unsettling, to put it mildly.

The wall has yet to rise, and digital surveillance technologies are still in development. But both the physical and virtual manifestations of Trump’s dehumanizing xenophobia don’t seem far off, as his hatred of the fictitious other festers and grows.