This article examines the relation between John Locke's doctrine of prerogative and constitutional government. Scholars have shown increased interest in Locke's doctrine in recent years, yet there is disagreement about its precise character. The Two Treatises of Government can be read such that this power is the result of the social compact and, thus, is a constitutional means of addressing emergencies. This paper instead argues that prerogative as it appears in the Two Treatises must be understood to be a natural power and, consequently, beyond constitutional control. It stands outside of the constitution because its logic denies that a good constitution is sufficient for liberal government.