Immanuel Kant and Samuel Pufendorf were both exercised by the relationship between politics, morality and lawful authority; a relationship that goes to the heart of the sovereign state’s existence and legitimacy. However, while Kant defended the authority of the moral law, believing morality provides higher authoritative norms than the sovereign state, Pufendorf defends the political morality of authority, believing the sovereign state should submit to no higher moral norms. The rivalry between these two positions is reprised in current debate between cosmopolitanism and statism over humanitarian intervention. Arguing against statism, this article defends a Habermasian-style critical international theory which affords a ‘cosmopolitanism without imperialism’.