罪刑法定原则与国际刑事司法实践对习惯国际法的发展

The Principle of Legality and the Development of Customary International Law by the International Criminal Justice

罪刑法定原则既是国际法治的内在要求,也是其外在表达。通过考察侵略罪(破坏和平罪)的历史变迁,我们发现国际刑事司法实践在发展习惯国际法的过程中始终面临着对罪刑法定原则的“回应”并有遵循该原则的“自觉”。一方面,由于习惯国际法在效力范围层面能约束所有国家,所以罪刑法定原则本身要求国际刑事司法机构只能适用习惯国际法或“重申了习惯国际法”的条约规则;另一方面,由于习惯国际法固有的特性,它始终处于一种演变发展的状态之中,这与罪刑法定原则所要求的规则明确性在形式上存在着相悖之处,亦体现了国际刑法与国内刑法的差异性。因此,国际刑事司法机构在通过认定、解释和适用习惯国际法来惩治国际犯罪之时,亦需证成其司法实践并未违反罪刑法定原则,即它对习惯国际法的发展应以罪刑法定原则为界,如果超出了这一界限,则有可能招致合法性质疑,罪刑法定原则亦由此贯穿于国际刑事司法实践对习惯国际法的发展这一命题的始终。

The principle of legality has been regarded as both an internal requirement and an external expression of the international rule of law.Taking the historical changes of Crime of Aggression(Crimes against Peace)as an example,this article observes the relationship between the principle of legality and the development of customary international law by the international criminal justice.From the identification of Crimes against Peace by the Nuremberg Trial and Tokyo Trial,to the development of Crime of Aggression by the Rome Statute of the International Criminal Court,it is found that,in the development of customary international law,the international criminal justice always faces the“response”to the principle of legality,and has the“consciousness”to uphold this principle or try to prove it still upholds the principle of legality,even when facing the most serious international crimes.On the one hand,since customary international law has binding force on all countries,the principle of legality requires the international criminal courts and tribunals can only apply customary international law or treaty rules that“reaffirm customary international law”.For example,regarding the applicable law by the United Nations International Criminal Tribunal for the Former Yugoslavia,in the view of the then Secretary-General of the United Nations,“the application of the principle nullum crimen sine lege requires that the international tribunal should apply rules of international humanitarian law which are beyond any doubt part of customary law so that the problem of adherence of some but not all States to specific conventions does not arise”.On the other hand,due to the inherent characteristics of customary international law,it is always in a state of evolution and development,which is contrary to the clarity of rules required by the principle of legality in form,and also reflects the differences between international criminal law and domestic criminal law.Therefore,When the international criminal courts and tribunals fight against international crimes by identifying,interpreting and applying customary international law,they also need to prove that their judicial practice does not violate the principle of legality.In other words,the development of customary international law by the international criminal justice should border the principle of legality.Otherwise,criticism on legality may arise.As a result,the principle of legality also runs through the proposition that the international criminal justice contributes to the development of customary international law.