Ward Farnsworth has penned a very good guest article at the Volokh conspiracy, on the subject of why politics is bad and trade is good.

Suppose the wreck of a ship is found on the ocean floor. Four teams race to lay hands on a treasure chest the ship is known to have on board; it contains artifacts worth ten million dollars. Each team spends about three million dollars trying to get there first. Eventually one of them succeeds, and the others are out of luck. Question one: do you see why this outcome is perverse?