The title of Professor Jessup's book implies a criticism of the existing, or "traditional" law of nations. That law is not, apparently, modern. What the author means can be gleaned from his first paragraph. The existing principles, institutions and procedures intended to govern the conduct of states and usually referred to as "international law," are not adequate to meet the conscious needs of today's world. Those needs find their sharpest expression in a widespread demand for a more reliable world order, one more capable of resolving peaceably conflicts between states, more capable of resisting the forces which periodically tear the fragmentary and weak existing order in shreds, and more productive of security for the individual in the legitimate pursuit of his interests.
Percy E. Corbett,
A MODERN LAW OF NATIONS,
Mich. L. Rev.
Available at: https://repository.law.umich.edu/mlr/vol47/iss1/7