The debate around Michels's “iron law of oligarchy” over the question of whether organizations inevitably become oligarchic reaches back almost a century, but the concept of oligarchy has frequently been left underspecified, and the measures that have been employed are especially inadequate for analyzing nonbureaucratically structured organizations. A conceptual model is needed that delineates what does and does not constitute oligarchy and can be applied in both bureaucratic and nonbureaucratic settings. Definitions found in the research are inadequate for two reasons. First, treating oligarchy solely as a feature of organizational structure neglects the possibility that a powerful elite may operate outside of the formal structure. A democratic structure is a necessary precondition, but it does not guar-antee the absence of oligarchy. Second, studies that equate oligarchy with goal displacement and bureaucratic conservatism cannot account for organizations with radical goals that are nonetheless dominated by a ruling elite. This article presents a model that distinguishes between legitimate and illegitimate forms of formal and informal power to define oligarchy as a concentration of illegitimate power in the hands of an entrenched minority. The model is intended for use in organizations that are nominally democratic to determine whether a formal or informal leadership has in fact acquired oligarchic control. By providing a common framework for tracking fluctuations in the distribution and legitimacy of both formal and informal power, it is hoped that this model will facilitate a more productive bout of research on the conditions under which various forms of democratically structured organizations may be able to resist oligarchization.
