Laser war is already here, and it might be so annoying it turns fatal. I am speaking not about directed energy weapons, the high-powered beams of light that most closely resemble the blasters and lasguns of science fiction. No, this is a simpler menace, one less about melting holes in objects and more on the side of blinding cameras and, occasionally, pilots.

The news in this particular case is a Notice to Airmen from the U.S. military, sent out April 14th and in effect until at least June 14th, warning pilots of a laser in use near China’s military base in Djibouti.

Lasers, even simple laser pointers used in a presentation or for entertaining cats, can incapacitate pilots if the beam gets them in the eye. The FAA has extensive rules for how to use lasers pointed at the sky, and guidelines for law enforcement on how to pursue people unlawfully lasering upwards. Lasers as intentional blinding tool dates back to the Cold War, where the eyes in question where not just human one but those of sensors, too.

“The active use of military lasers extends to their usage as weapons per se as opposed to being mere accessories to other weapons,” wrote Jack H. McCall Jr, for the Cornell International Law Journal in 1997. McCall continues:

McCall was writing in the wake of the passage of the Protocol on Blinding Laser Weapons, part of the Geneva Conventions on Certain Conventional Weapons. An international agreement to stop the use of lasers against humans in war was heralded as a “Triumph of civilization over barbarity,” a phrase that conjures to my mind an amazing image of Asterix and Obelisk wielding rayguns.

So, what was the actual barbarity in question? McCall cites an instance in the 1982 Falklands War between the United Kingdom and Argentina where it’s possible a British laser dazzler caused three Argentinian aircraft to fatally crash. McCall also notes a possible earlier use of laser rangefinders on Soviet tanks as a blinding weapon against Chinese troops in the 1970s, and the possible use of laser rangefinders as a blinding tool by Iraqi forces against Iranian forces in the mid 1980s. And in the late 1980s, Pentagon reported incidents of Navy planes harassed by Russian lasers. Beyond adapting lasers built for other purposes into weapons, at the time of the Protocol on Blinding Laser Weapons, the United States and China both had some development into lasers specifically for this purpose, though the extent of the research varied.

As for the treaty itself, it has two rather large exceptions written into it on the use of lasers for war. The first that, while it prohibits weapons “specifically designed, as their sole combat function or as one of their combat functions, to cause permanent blindness to unenhanced vision,” it does not appear to rule out the use of lasers designed for other purposes that may be used circumstantially as a weapon. That’s the weaker exception, though one that may have played into the development of some laser-based weapons billed as less-lethal.

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The greater exception is Article 4, which states “Blinding as an incidental or collateral effect of the legitimate military employment of laser systems, including laser systems used against optical equipment, is not covered by the prohibition of this Protocol.” If the laser is designed to work against camera pods, it’s a legitimate military use, and if the laser targets uninhabited vehicles (like drones), there’s nothing in the protocol against it. A focus on non-human targets has meant that lasers can be developed to blind satellites, creating a much less explodey option for anti-satellite warfare. It’s possible that high-powered lasers reported in the notice-to-airmen are designed at sensors, but also operating in the visible light spectrum, where it’d be irrelevant for infrared or other wavelengths commonly captured by cameras.

Is there a laser war happening off the coast of Djibouti? Unlikely, but there’s reason to suspect someone might be testing a laser as a weapon.