The historical development of western civilization has produced several patterns of political opposition deeply rooted and relatively well established in the political systems. This opposition is usually identified with the control of the governed over the government : it is maintained that opposition is at the same time a sufficient and a necessary condition for the existence of such control. Opposition, as the term is commonly used, has the following characteristics : (a) it is political; (b) it is institutionalized in the form of a party or parties; and (c) it is often said that it is also ‘responsible’, i.e., it does not extend to obstruction of the government's actions. In order to define more precisely the relationship between opposition and control, we must ask two questions of a more specific nature: (i) is opposition a sufficient condition for effective control? And (ii) is it a condition sine qua non for any kind of political control? In spite of some ideological assertions, it seems clear that the answers to both questions are negative. Since the problem of opposition in the two- and multiparty systems is discussed elsewhere, we shall focus here on those mechanisms of control which present an alternative to opposition as institutionalized in the party system.