drop in crime, it almost certainly didnt affect criminal behavior in any significant way. Unless, that is, "the economy" is construed in a broader sense-as a means to build and maintain hundreds of prisons. Lets now con- sider another crime-drop explanation: increased reliance on prisons. It might help to start by flipping the crime question around. Instead of wondering what made crime fall, think about this: why had it risen so dramatically in the first place? During the first half of the twentieth century, the incidence of vio- lent crime in the United States was, for the most part, fairly steady. But in the early 1960s, it began to climb. In retrospect, it is clear that one of the major factors pushing this trend was a more lenient justice system. Conviction rates declined during the 1960s, and criminals who were convicted served shorter sentences. This trend was driven in part by an expansion in the rights of people accused of crimes-a long overdue expansion, some would argue. (Others would argue that the expansion went too far.) At the same time, politicians were growing increasingly softer on crime-"for fear of sounding racist," as the economist Gary Becker has written, "since African-Americans and Hispanics commit a disproportionate share of felonies." So if you were the kind of person who might want to commit a crime, the in- centives were lining up in your favor: a slimmer likelihood of being convicted and, if convicted, a shorter prison term. Because criminals     respond to incentives as readily as anyone, the result was a surge in crime. It took some time, and a great deal of political turmoil, but these incentives were eventually curtailed. Criminals who would have pre- viously been set free-for drug-related offenses and parole revocation in particular-were instead locked up. Between 1980 and 2000, there was a fifteenfold increase in the number of people sent to prison on drug charges. Many other sentences, especially for violent crime, were