First, the author shows that the law and the Constitution impose few restraints on the criminal justice system's use of predictions and classifications. A survey of the debate between those who believe in limited State power and those who believe in extensive State powers focuses on four issues: appropriateness of increased punishment or State intrusion into the lives of those predicted to be dangerous; disparities in outcome that result from using predictions; low levels of accuracy of such predictions; and their disparately harsh impact on minorities and the poor. An emerging consensus supports a system which limits the scope for increased punishment or intrusion based on predictions and forbids reliance on information related to social status. In this framework, primary reliance is based on prediction variables related to current offense and prior conviction. The author advocates replacing existing criminal codes with new ones that define offenses in greater detail and allow shorter maximum sentences. Tables and approximately 40 references. (Author abstract modified)