This book analyses the tendency in international law scholarship and criticism to seek a ‘new’ international law. Drawing and building on scholarship around the political significance of theological ideas, it argues that underlying this tendency is a relationship between international law and messianic thinking. Demonstrating that messianism has been, and continues to be, a telling quality of much international legal thought, the book also traces its broader implications; particularly with regard to the use of violence and the perpetuation of global inequalities. The temptation to project onto international law the hoped-for realisation of a new world obscures both the failures of international law and a proper appreciation what it can achieve. As such, international law, it is argued, must be radically reconceived if it is to avoid the traps of determinism and the false universalism inherent within the dominant form of messianism in international law.