Where does the reform oriented planner get his authority to propose social change? A review of city planning experience suggests four sources of authority: expertise, bureaucratic position, consumer preferences, and professional values. In a parallel fashion, social reformers have looked to elite institutional interests, social science research, and client participation in their search for legitimacy. The dilemma is that individually each approach limits the effectiveness of planning, yet the various sources of authority are mutually exclusive and cannot be pursed together by one planning organization. The difficulties of this choice between approaches are central to the education of social policy planners.