About 5 percent of the world’s population lives in the United States. However, one in four of the world’s prisoners is incarcerated here. Fordham Law School professor John Pfaff joins us to talk about why the U.S. has such a high rate of imprisonment – and about ways to curb that population. He writes about the topic in “Locked In: The True Causes of Mass Incarceration and How to Achieve Real Reform” (Basic Books).