Autonomy slowly builds as weapons systems get upgraded over time, Scharre said. A missile that used to home in on a single enemy might get a software upgrade allowing it to track multiple targets at once and choose the one it’s most likely to hit.

Technology is making weapons smarter, but it’s also making it easier for humans to control them remotely, Scharre said. That gives humans the ability to stop missiles even after they’re launched if they realize after the fact they might hit a civilian target.

Still, the demand for speed in war will inevitably push militaries to offload more decisions to machines, especially in combat situations, Kayser said. It’s not hard to imagine opposing algorithms responding to each other faster than humans can monitor what’s happening.

“You saw it in the flash crashes in the stock market,” Kayser said. “If we end up with this warfare going at speeds that we as humans can’t control anymore, for me that’s a really scary idea. It’s something that’s maybe not even that unrealistic if these developments go forward and aren’t stopped.”