The first 50 years after 1925 showed a relatively flat pattern in imprisonment trends. The next 25 years, however, saw the rate of imprisonment in the United States more than triple. Starting in 1973, the U.S. prison population increased every year for 30 years. Among the theories that have been proposed to explain this trend are increasing crime rates, changing public attitudes toward crime and criminals, political conservatism, and a crisis of modernity. Each of these theories has some empirical support in U.S. history after 1970; however, when the United States is compared with other nations that did not experience the same changes in imprisonment policy, support for most of these theories weakens. The author notes that what distinguishes America from Canada, France, and Australia during the 1970s and 1980s was the level of public fear and priority concern about crime driven by high levels of lethal violence and associated panic over the epidemic of crack cocaine. Punitive public attitudes toward crime and criminals impacted imprisonment rates in the United States more than in other democratic countries due to the anger and fear that swept through the public and became prominent in political campaigns. The subsequent political trend that institutionalized excessive imprisonment was the establishment of fixed and mandatory imprisonment as well as the elimination of parole. If the trend toward the massive imprisonment of convicted offenders is to be reversed, sentencing decisions must be removed from the political sphere and returned to trained professionals who will tailor their sentencing decisions to the individualized rehabilitative needs of offenders. 11 references