現代國際法中之訴諸戰爭法與戰後法之發展

Jus ad Bellum in Modern International Law and the Development of Jus post Bellum

現代國際法在武裝衝突領域有兩大分支：訴諸戰爭法與戰時法，前者節制國家行使武力的時機，後者規範武裝衝突中的行為，本文聚焦於探討訴諸戰爭法。訴諸戰爭法受歐洲基督教文明下的正義戰爭理論影響甚鉅，且係以宗教觀點評價戰爭的正義性；主權國家出現後，戰爭成為實行外交或國家政策的手段，戰爭正義性與否不再重要，取而代之的是以法律規制戰爭。傳統國際法承認國家有發動戰爭的權利但須合乎特定程序，迄至第二次世界大戰後，聯合國憲章完全禁止戰爭，僅在例外條件下容許使用武力，因此，現代意義下的訴諸戰爭法係規範國家間使用武力的法。
即使現代國際法要求原則上不訴諸武力，武裝衝突仍頻繁發生，正義戰爭理論於此復興，主張不僅開戰與作戰正義，戰後階段也應達到公正且持久和平，此見解為部分法律學者所接納並發展戰後法的概念，成為武裝衝突法領域第三分支，在時間性方面，訴諸戰爭法、戰時法與戰後法正好可對應武裝衝突的開始、進行與結束，在功能性方面，戰後法可以發揮從武裝衝突過渡到和平的作用。對於國際社會而言，戰後法是相對較新穎的概念，儘管戰後法的定義與具體內涵尚未有共識，此部分應該值得持續研究。

There are mainly two branches in the field of law of armed conflict in modern international law: jus ad bellum and jus in bello. The former deals with recourse to war, while the latter regulates the conduct of war. This article focuses on jus ad bellum. In medieval age, jus ad bellum was greatly formed by the bellum justum, which was influenced by Christian civilization in Europe. In other words, the criteria for resorting a just war were developed from a religious perspective. After sovereign states emerged, war became an instrument of national policy in their relations with one another. It is totally irrelevant today whether a war is just or not. Instead, the war is restricted by law. Although the right to resort to war was recognized in traditional international law period, it must comply with certain procedures. After World War II, the United Nations Charter completely prohibited war. States are only allowed to use force under exceptional circumstances. Therefore, the jus ad bellum in modern time is a law that regulates the use of force between states.
Even though international law requires states undertake the obligation not to resort to force arbitrarily, armed conflicts still occur frequently. At this time, the just war theory is revived. Some scholars argue that a just and lasting peace should be achieved in the post-war period. This thought is accepted by several jurists. They believe that jus post bellum may construct the third branch of law of armed conflict. From temporal view, jus ad bellum, jus in bello and jus post bellum can exactly correspond to the beginning, progress and end of an armed conflict. From functional view, jus post bellum can play a role in the transition from armed conflict to peace. For the international community, jus post bellum is a relatively new concept. There is no consensus on the definition and specific connotation of law after war though, this issue should be worthy of research constantly.