For the past couple of months, I’ve been building myself a surveillance drone. My craft consists of a remotely controlled quadcopter – a small helicopter with four rotor blades that looks like a flying X – with an onboard video camera that sends a live feed back to my laptop base station. It also transmits telemetry data about its altitude, speed, bearing and location from its onboard global positioning system receiver. In future, I plan to equip the aircraft with an autopilot system that will allow it to fly from one GPS-specified location to another without my having to pilot it.

I decided I had to have my own drone after hearing about the US army’s RQ-11 Raven, made by a company called AeroVironment. This drone is no more than a glorified remote-control aircraft that a soldier launches by tossing into the air. It can send video back to the squad so they know whether, for example, there are bad guys lurking behind the building in front of them.

I don’t have too many terrorists lurking in my neighbourhood near Stanford. On the other hand, I’ve done a good deal of photography over the years as a hobby. I thought it would add another dimension, quite literally, if I could photograph, say, the Coastal Redwoods not just from the forest floor, but from above the tops of the trees. Frankly, however, now that I’ve started this project, the motive has shifted to one of pure technological empowerment. I’m astonished at what home-made drones can do, and at the fact that there’s an enthusiast group called DIY Drones with more than 20,000 members who are busy programming new controllers and making the technology readily available to ordinary people.

We are of course familiar with the way drones have changed the nature of war in Iraq and Afghanistan. Armed drones such as the Predator and Reaper have struck deep into Pakistan, where they are used to target individual Taliban commanders with deadly accuracy. By next year, the Air Force will have more drone pilots than pilots of F-16s. Flown from half a world away in the Nevada desert, they have given the US a means of projecting power far into another sovereign country with no risk of an American airman being shot down and captured, as U-2 pilot Francis Gary Powers was back in 1960. They are also controversial, since they periodically kill innocent civilians, and are one important reason for the disastrous state of US-Pakistan relations today.

The technology is not standing still. Down the road are insect-sized drones that could be mistaken for a housefly or spider, which could slip in under a door-sill to record conversations, take photos or even inject a lethal toxin into an unsuspecting victim. Systems such as these are under development by the Army’s Micro Autonomous Systems and Technology (Mast) programme, in partnership with a variety of corporations and university labs. Further into the future are nanobots, particle-sized robots that could enter people’s blood streams or lungs.

At the moment, the chief concern about the domestic use of drones is privacy. My drone could be used to look inside a neighbour’s third-floor window, or at a private party or an exclusive construction site – though, of course, I would never ever be tempted to use it for such a thing.

The American Federal Aviation Authority used to restrict the commercial use of drones for purposes such as real estate snooping or crop dusting, but a new law makes all of this legal. Several civil liberties groups have warned that the proliferation of cheap drones will make Americans rethink how much privacy they really have, given technological change.

But there are longer-term dangers involving criminal or violent uses of drone technology – such as targeted killings, which can now take place at much longer range than previously. US law makes a distinction between government-sponsored assassinations, which have been illegal since 1976, and targeted killings, which are performed every day in Afghanistan and Pakistan. The latter are supposedly done only in self-defence, but there are no generally accepted rules for how this should be defined. As the defence budget shrinks, targeted killings by drones and special forces will seem an attractive way to project power on the cheap.

Surely, however, America’s rather liberal use of this technology has something to do with the asymmetry of power between the US and its current opponents in places such as Pakistan, Somalia and Yemen. But this situation will not last for ever. Drone technology is within the reach of many countries, and has been filtering down to ordinary consumers year by year. (Much of the hobbyist drone technology comes from China, even now.) If I can have my own surveillance drone, anyone can.

What will the world look like when not just the US but many other countries around the world operate fleets of drones; and when powerful, sophisticated drones are owned by lots of private individuals? What would our attitude be if our enemies could pick off visiting dignitaries as they stepped off the aeroplane in a supposedly friendly country, or attack soldiers in their bases in Europe or Asia? Or if Americans became vulnerable in Florida or New York? Drones might become an inexpensive delivery vehicle for terrorists or rogue states that can’t afford to deliver payloads in ballistic missiles. Some of the remotely controlled aeroplanes that hobbyists build are a third to half the size of their full-scale counterparts. As the technology becomes cheaper and more commercially available, moreover, drones may become harder to trace; without knowing their provenance, deterrence breaks down. A world in which people can be routinely and anonymously targeted by unseen enemies is not pleasant to contemplate.

Drones have plenty of legitimate uses, in police work, traffic control and farm management. Pressure from these users is why the FAA liberalised its rules, making it a great wild west out there for hobbyists and tinkerers. Only when people start thinking through the nature of a world in which drones are cheap and ubiquitous will they start to get worried. That’s why I want to build mine now, before the government makes them illegal.

The writer is a senior fellow at Stanford’s Freeman Spogli Institute. His latest book is ‘The Origins of Political Order: From Prehuman Times to the French Revolution’

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