Humanitarian Intervention


The Dutch lawyer, statesman and diplomat Hugo Grotius (1583-1645) conceived of international law as analogous to moral relationships between persons. This means - according to Grotius - that moral laws apply equally to both the individual and the state. 

In his major work De iure belli ac pacis (1625) Grotius sets out the basic principles of international law. Among these principles are the moral requirements for resorting to the use of armed force (ius ad bellum) and the criteria for justifiable use of such force (ius in bello). The moral requirements of ius in bello are that a use of armed force be discriminate and proportionate. For ius ad bellum, the requirements are that the resort to force (1) have a just cause, (2) be authorized by a competent authority, (3) be motivated by moral intention, and (4) pass four essential tests: it must (a) be expected to produce a preponderance of good over evil, (b) have a reasonable hope of success, (c) be a last resort, and (d) have peace as its expected outcome.