Since 9/11, the U.S. has grown increasingly reliant on drones to take out suspected terrorists in far-flung regions of the globe. The trend has only accelerated under President Obama, who has coupled a surge in drone attacks with a withdrawal of troops in Afghanistan and Iraq, a clear signal that the U.S. fight against terrorism will no longer entail a large military footprint on the ground. And as the troops recede, the drones are only going to get smaller, more accurate, and deadlier, according to John Horgan at National Geographic. Horgan says the Air Force has constructed a "micro-aviary" to test insect-like drones, and he was given an animated video that shows simulated drones in action. According to Horgan:

The drones swarm through alleys, crawl across windowsills, and perch on power lines. One of them sneaks up on a scowling man holding a gun and shoots him in the head. The video concludes, "Unobtrusive, pervasive, lethal: Micro air vehicles." [National Geographic]

The possibility of a world filled with micro-drones has disconcerted some commentators. "Sure, we have a technological advantage right now," says Conor Friedersdorf at The Atlantic, "but micro-drones seem like a disruptive technology that will eventually help rather than hinder attempts at asymmetric warfare." However, if the micro-drones of the future in any way resemble those depicted in the video, it would presumably reduce the number of innocent civilians that have been killed by drone strikes, one of the most potent moral arguments against using drones.