Jus ad bellum에 있어 필요성·균형성 원칙의 기원

The principles of necessity and proportionality in jus ad bellum have a long history associated with the history of the regulation of the resort to force over the years. In just war theory, necessity, in the sense that war is a last resort when other means have failed to achieve the object, is inherent, and proportionality was concerned with an assessment of whether the overall evil of resorting to war was balanced by the overall good that would be achieved. In the latter part of the eighteenth century and in the nineteenth century, the resort to force became unregulated following the decline of just war theory. Nevertheless necessity and proportionality in jus ad bellum did not fall into entirely into disuse. As for necessity, states in reality attempted to justify their forceful actions on a number of grounds. States may not have felt constrained to consider the proportionality in an overall sense that the resort to force would do more harm than good. It was inevitable that owing to the demise of the just war theory and the growth of the modern system of nation states, there would be a gap for a time until states realized it as being in their interests to develop a new system to regulate the resort to force. The practices, considering whether force was necessary and, if so, to what extent, gradually emerged. It was during this era that 1837 Caroline Incident occurred. Here appeared the modern requirements of legitimate self-defence, namely, necessity and proportionality. This formulation is also valid under the United Nations Charter system.