Mercenaries: The History of a Norm in International Relations

The main aim of this book is to argue that the use of private force by states has been restricted by a norm against mercenary use. The book traces the evolution of this norm, from mercenaries in medieval Europe through to private security companies in modern day Iraq, telling a story about how the mercenaries of yesterday have evolved into those of today in the process.

The norm against mercenaries has two components. First, mercenaries are considered to be immoral because they use force out...