The relative shortness of the length of prison sentences is probably a main reason for the humaneness of the Dutch prison system in comparison to other prison systems. Although the rise in crime is a possible consequence of the Dutch sentencing policy, it is probably attributable to more fundamental social and economic developments. The sentencing policy appears to have gone through three major phases since World War II. From the late 1940's to the mid-1960's, the impact of a rehabilitative philosophy seems crucial in explaining the trend towards shorter sentences. From the mid-1960's until the mid-1970's, the falling clearance rate and other constraints assumed increasing importance in enabling the judiciary to effect a continuation of these trends. Since the late 1970's, the period of shortening sentences has ended, and pressure to expand the capacity of the system is working through the political process. Tables.