The issue of armed police robots is a contentious one. And while the U.S. is pulling back from the idea, Nigeria’s national police have just received their first shipment of armed drones from Turkey.

Spot isn’t like other police dogs. For starters, it has no head. Or fur. And instead of kibble and water, it runs on a lithium-ion battery. When the four-legged robot, which can climb stairs, open ...