I’m not really a weapons designer, but it’s only a small extrapolation from the DARPA FLA program (small high-speed quadcopters zooming in and out of buildings) and the CODE program (“hunting in packs like wolves”) to imagine dumping truckloads of flying microrobots the size of large insects, each carrying a 1g shaped charge to blow holes in peoples’ heads or a microrifle to shoot their eyes out. They might need some larger ones to blow holes in doors and walls and stop vehicles. They are totally expendable and very cheap. Planners also seem to be thinking about naval and air-to-air combat which would involve much more expensive assets, but the principle is the same — overwhelming numbers, cooperative behaviors, etc.
So we’re in a new era here. The obvious analogy is to the development of nuclear weapons. Oppenheimer and Szilard warned of an arms race and lost the argument to Teller, Von Neumann and others who wanted to go full speed ahead. The U.S. and Soviets built massive arsenals and placed each other under the threat of nuclear doomsday for decades. Arms control treaties have made the world safer, though. And scientists and engineers have often recognized that there are no-go zones. When gene-splicing became possible, everyone called time-out and held a big conference at Asilomar. More recently, scientists called for a ban on gene-editing with the “crispr” technique.