The advent of military drones and their rapidly expanding portfolio of capabilities has already had a major impact on the future of warfare planning across the United States. The Pentagon has launched a major program to build a new artificial intelligence for controlling its own drone efforts, and Google is helping it. Concern over the long-term impact of low-cost missiles and drones drove the Navy’s research into railguns and other delivery vehicles with lower-cost projectile systems until those programs were shelved. Legal experts and military tacticians have both debated how the use of remote autonomous vehicles could challenge existing views on the use of force across the military and in civilian encounters.

But our view of a military drone as an expensive, large, fixed-wing aircraft with a bevy of sophisticated onboard sensors and capabilities may rapidly be as obsolescent as the idea of wooden-hulled battleships. As a recent story in The Atlantic points out, rapid advances in drone technology are making it easier to deploy incredibly primitive “drones” that are still capable of doing real damage.

The National Academy of Science was recently commissioned to write a report on the risks of small unmanned aircraft systems (sUAS) and whether the military’s existing timetable for evaluating and developing responses to existing threats is satisfactory. The subsequent report wasted few words, stating:

The U.S. Army’s force capability timeframe is too drawn out to address the rapid advancements in sUAS performance capabilities and anticipated threat uses. This is because potential adversaries are improving their sUAS capabilities on commercial and consumer developmental timelines.

FAA investigations into a single drone firing a handgun make headlines in the US — and to be sure, that’s something civilian law enforcement should absolutely care about — but forget about the dubious mechanics of trying to fire a weapon aboard a moving platform with a weight measured in ounces. A simple drone built out of plywood can carry and drop a hand grenade. Russian drones carrying a pound of thermite are believed to have destroyed two Ukrainian ammo depots last year, in July and September. And an entire swarm of primitive drones struck Russian forces in Syria this year. Of the 13 drones that struck Russia’s Syrian HQ, seven were shot down and six brought down by electronic countermeasures. While the Russians defeated this attack, it proves the point — militias and guerilla organizations working with minimal tools can now build drones capable of launching attacks.

The US military has invested in electronic countermeasures, believing that the key to stopping drones is the use of jamming. But as drones become more proficient at making decisions on their own, the need for a remote uplink could vanish altogether. And as the report notes, simply shooting at the diminutive drones isn’t a great option for stopping them.

“Kinetic counters, such as shooting down a single, highly dynamic, fast-moving, low-flying hobby aircraft with small arms (rifles, shotguns, and light machine guns), are extremely difficult due to the agility and small size of sUASs,” the report states. “Additionally, swarming sUASs can be employed to overwhelm most existing kinetic countermeasures.”

The United States is working on its own drone swarms, including a recent test of a deployment of more than 100 robin-sized micro-drones designed by Perdix from a pair of F-18s. The Perdix drones are being built as part of research into using large swarms of drones with a distributed intelligence. The goal is to use them for unmanned aerial surveillance, taking advantage of the fact that it’s much harder to hit a bunch of tiny drones than a single large target like a Predator drone.

It’s not clear yet what an effective response to this attack strategy will look like. The military still grapples with fighting guerilla and insurgent forces effectively because the nature of civil conflict within states is, for various reasons, a difficult problem for conventional armed forces to confront. The advent of cheap, easily assembled drone swarms serving as a micro-bombing fleet could make such situations worse. How do you identify and strike military centers when the “air force” attacking you can be assembled largely from scrap and cobbled-together components, powered by a “brain” equivalent to a midrange smartphone, and launched from a parking lot?