AS A CHILD, Peter Leeson was pirate-obsessed. He cherished the ruby-eyed skull ring he got at Disney World, after riding Pirates of the Caribbean. He took up a collection of coconut pirate heads. He lapped up the pirate themes in "Goonies." And when he grew up to be an economics professor, and started studying pirate society, he found a new excuse for admiration. Pirates, it turns out, were pioneers of democracy. Presidential candidates, take note: Long before they made their way into the workings of modern government, the democratic tenets we hold so dear were used to great effect on...