It is time to impose law and order on the frontierIllustration: Brett RyderBARBED WIRE held a strange interest for the late Alan Greenspan, a lifelong urbanite. Sure, the former Federal Reserve chairman admired the railways, gold diggers and “lonesome cowboys” that helped open the frontier at the dawn of American capitalism. But he also had a soft spot in his economist’s heart for barbed wire, which, he argued, boosted productivity by allowing the settlers who came in their wake to safeguard the...