Nonviolent action will produce attitude change to the exlent that it satisfies either or both of two prerequisites. It must either interfere with the functions served by the attitudes or it must produce some inconsistency between the attitudes and other orientations of the persons affected by the action. The three major functions served by attitudes are object orientation, ego‐support, and ego‐defense. For many social attitudes the ego‐support provided by attitudes which help define a person's relation to a reference group is especially powerful, Functions may be blocked by a particular set of conditions, which may have little in common with one another. Inconsistencies may occur among different attitudes or among the components of a single attitude. One class of inconsistencies that is of particular importance occurs when people are persuaded or mildly pressured into action contrary to their attitudes. Each of the sources of attitude change pressure carries its own requirements for producing change and its own mechanisms for protecting attitudes against change pressures. Nonviolent action does not necessarily meet these requirements or overcome the defenses. However, with knowledge of the functional bases and conceptual contexts of the attitudes being challenged it may be possible to utilize the resources present in nonviolent action to increase the likelihood of a desirable i