International Constitutionalism: the Tools of Recognition

International law as domestic legal systems may not has a codified constitution, but it can use constitutionalist approach in reading and interpretation of its rules. This paper studied how can recognize this approach, its hidden values and legal consequences, then introduce various tools and shows that natural law has an important role in strengthening constitutional approach, also international courts can apply rational intuitionist approaches to recognize constitutional norms. This study by descriptive research method concludes that recognition of constitutional values and norms is by rereading contractual and customary norms, and it affects general reading and understanding of legal order.