Sharp defines political power, which is one type of social power, as 'the totality of means, influences, and pressures - including authority, rewards, and sanctions - available for use to achieve the objectives of the power-holder, especially the institutions of government, the State, and groups opposing either of them' (1980, p. 27).

The essence of Sharp's theory of power is quite simple: people in society may be divided into rulers and subjects; the power of rulers derives from consent by the subjects; non-violent action is a process of withdrawing consent and thus is a way to challenge the key modern problems of dictatorship, genocide, war and systems of oppression.