Authority is often defined as legitimate power, and contrasted to pure power. In the case of legitimate authority, compliance is voluntary and based on a belief in the right of the authority to demand compliance. In the case of pure power, compliance to the demands of the powerful is based on fear of consequences or self-interest. But beyond this, there is considerable disagreement and variation of usage. Because legitimacy is a concept from monarchic rule, deriving from the right of the legitimately born heir to rule as monarch, authors as diverse as Hannah Arendt and Carl Schmitt have argued that it is not applicable to modern politics. But it is nevertheless commonly applied, even in ordinary political discussion, to many situations, such as voluntary compliance to taxation, that go far beyond the original meaning.