The international community has struggled to adopt a cohesive response to Islamist terrorism since the late 1990s. Member states of the United Nations have, therefore, been accorded significant discretion in how they react to terror threats. The United Kingdom, for example, has embraced a pro-security agenda in the number of legislative responses it has enacted, together with the breadth of criminalisation these statutes employ. The theory of the social contract is particularly applicable to the difficulties modern countries face in drawing (...) the line between liberty and security. Thomas Hobbes and John Locke traditionally theorise opposing ends of this spectrum. But contemporary security discourse has often overlooked the philosophical contribution of another theorist of the same era as Hobbes and Locke, Jean-Jacques Rousseau. Where does Rousseau present on the liberty/security divide? Do his writings represent a theoretical model for the UK’s pro-security response since 9/11? These are the questions this piece seeks to answer. (shrink)