You could be forgiven for thinking that a label on a map—in this case the British Indian Ocean Territory, or BIOT, pronounced somewhat like “buyout”—is something you could take at face value. I own a coffee mug emblazoned with the territory’s coat of arms: a Union Jack, a crown, a palm tree, and some wavy lines representing water, all displayed on a shield supported by two sea turtles. I have seen coins and stamps from the territory, and have frequently come across the domain name .io (for Indian Ocean). This entity has a flag, a website, and a commissioner in London. And there is some dry land associated with the name: the 60 or so low-lying tiny islands of the remote Chagos Archipelago, spread across 6,000 square miles of sea, near the Indian Ocean’s geographic center. I stepped foot on several of the islands last year, bringing back a vial of fine white sand that I hoped customs authorities wouldn’t mistake for something else. BIOT was created in the 1960s as a useful fiction. The …