The Pentagon has authorized the Department of Homeland Security (DHS) to test a military-grade heat ray for possible use along the US-Mexico border. The move opens a new chapter in the Trump administration’s efforts to expand immigration enforcement technology.
But the weapon, designed to drive away people through an intense burning sensation, comes with difficult questions about safety, legality, and whether it is necessary at all.
According to CNN reporters Zachary Cohen and Priscilla Alvarez, a memo signed by Defense Secretary Pete Hegseth last month permits DHS to borrow the weapon for seven months, beginning in September 2026. The authorization allows the department to test the technology and develop tactics for its potential deployment in border operations.
The proposal is significant because, despite previous military experiments and years of discussions among border officials, the system has never been deployed against migrants at the US-Mexico border.
How the Heat Ray Works, and Why Officials Want to Test It
Officially known as the Active Denial System (ADS), the weapon uses directed electromagnetic energy to produce an intense heating sensation on exposed skin. According to the US military, its invisible beam can reach a little more than half a mile.
Military officials have compared the sensation to opening a hot oven and encountering a sudden blast of heat. The resulting effect is intended to make people instinctively move away from the beam. Pentagon descriptions say the tingling sensation generally lasts between 10 and 15 minutes, accompanied by what officials have called an “instinctive and irresistible urge to run from the effect.”
The system is classified as nonlethal, meaning it is designed to discourage or disperse people without killing them. However, that label does not mean it is incapable of causing injury or producing dangerous consequences in particular circumstances.
For Customs and Border Protection (CBP), the attraction appears to be the possibility of controlling groups of people without relying exclusively on physical barriers or conventional force. Officials have previously discussed using the technology in areas experiencing concentrated illegal crossings, including locations where migrants attempt to cross rivers.
A CBP spokesperson told CNN that the agency was “continually evaluating new technologies, especially those that enhance operational effectiveness and strengthen mission capabilities.”
It’s noteworthy that the statement did not confirm where the system would be tested, how it would be used, or whether deployment against migrants is planned.
A Weapon with a Complicated History
The authorization follows years of internal debate over whether the ADS belongs in immigration enforcement.
CNN reported that the US military briefly deployed the system to Afghanistan nearly two decades ago but ultimately declined to use it during active combat operations. Officials also considered employing it for crowd control at American facilities overseas holding terrorist detainees, but those plans were abandoned.
On the domestic front, officials considered the possibility of using the weapon during periods of unrest, including protests following George Floyd’s murder in 2020. Border officials also examined its potential in California’s El Centro sector, where agents were concerned about crossings near a river.
The technology might have discouraged people from entering the water or encouraged those already crossing to leave it. Yet that scenario exposed a central problem: forcing someone to flee does not guarantee they will flee somewhere safe.
One former CBP official told CNN: “Even if they’re chasing people back to the river, you don’t want them to go in and drown.”
The official questioned whether the expense, training requirements, and new operational policies would justify the benefits, asking: “For the cost, for the training, and for the policies you’re going to create, is the juice worth the squeeze?”
In 2018, CBP officials also considered using the weapon against migrants, but then-Homeland Security Secretary Kirstjen Nielsen rejected the idea. A former DHS official described the underlying concern to CNN as “treating immigrants and citizens like enemy combatants.”
Safety, Sovereignty, and the Question of Necessity
The latest authorization leaves several important questions unanswered. The memo permits a temporary loan of one system and specifies that it “shall not be operated by DoW (Department of War) personnel.” DHS is assigned sole responsibility for “system employment, use, and development of tactics, techniques, and procedures.”
The border is now a military installation and a battle lab for testing new systems, to include directed energy weapons. The border is locked down! @DoWCTO pic.twitter.com/d3FeOSxEun
— Patrick Weaver (@PatrickWeaverPA) October 21, 2026
That division of responsibility raises questions about accountability if the technology is eventually used operationally. The Pentagon referred CNN to DHS when asked for comment.
Officials have also wrestled with jurisdictional concerns, particularly the prospect of directing the weapon at people still in Mexico. Using it across an international boundary could raise sovereignty and legal questions, while any injuries or deaths resulting from people fleeing into rivers or other hazards could complicate claims that the weapon is nonlethal.
There is also a practical question about demand. A former CBP official told CNN that some Border Patrol agents have questioned the need for the system given low border crossings and increased staffing.
For now, the seven-month authorization permits testing and tactical development, not proof that the heat ray will become a regular feature of border enforcement. Whether it advances beyond experimentation will depend on its effectiveness, safety, cost, and the legal framework governing its use.
The technology may offer border officials another way to influence human movement. The harder challenge is demonstrating that it can do so without creating new risks for the very people it is intended to move.
A further development strengthens the significance of the authorization: after CNN published its report, Hegseth’s deputy chief of staff posted on X that “The border is now a military installation and a battle lab for testing new systems to include directed energy weapons.” CNN reported that the Pentagon would be watching closely for lessons from DHS testing.