While a national movement for sentencing reform had emerged by the mid-1970's, new laws adopted in several States differed markedly from one another. Studies had documented sentencing disparity prior to this period, but the growth of liberal groups interested in the issue supplied support and impetus to both national and local reform efforts. A description of the justice model, the philosophical basis for most liberal opinion on sentencing disparity, focuses on a project conducted by the U.S. Board of Parole and the National Council on Crime and Delinquency which identified implicit factors that explained much variation in the parole board's decision and then tried to make these factors explicit through a matrix system. It also reviews various schemes to limit judges' discretion. Most proposed sentencing reforms attempt to balance two competing values, societal protection and individual liberty, but encounter difficulties in achieving these goals when they are operationalized in a working sentencing system. California enacted the Uniform Determinate Sentencing Act in 1976, creating a presumptive sentencing system that contrasted sharply with its previous emphasis on indeterminate sentencing and rehabilitation. In 1977, Oregon passed a bill requiring proportionality in criminal sanctions and the structuring of parole release discretion through criteria, including ranges of imprisonment. The paper examines these two different approaches to sentencing reform, describing the ways in which forces in each State influenced the type of system adopted. The author concludes that effective reformers obtain broad-based support and maintain control by limiting the scope of their proposals and minimizing the possible negative impacts of reform on large correctional agencies. Reformers are most successful when they compromise with opponents on specific provisions. It appears that a person or group can control the reform process if he/she or they are determined enough, because few individuals actually write legislation and the legislative process is based on bargaining and compromise. The paper contains 22 footnotes and 50 references. See NCJ-87442.