ABSTRACT
Hans Kelsen, the bitter antagonist of natural law, became the principal champion of the doctrine of bellum justum, which he felt compelled to defend for wholly logical reasons. If war cannot be interpreted either as a delict or as a sanction against a delict, then it is no longer possible to consider international law as law at all. But in his most recent treatment he does not decide whether this doctrine is a norm of positive international law, and states forcefully the grave objections against the workability of this doctrine. While Catholic international lawyers, such as Mausbach and Cathrein, retained the traditional concept of bellum justum, the revival was inspired by very different motives in other writers. The concept of bellum legale replaced the concept of bellum justum. The illegality of resort to war was not a function of the intrinsic injustice of the cause of war, but of the breach of a formal, procedural requirement.
