The Relationship between International Law and National Law : A Case Study of Thai Judicial Practice

Abstract

Every State has a duty to comply with international obligations and cannot invoke an inconsistency of national law as an excuse for failure to perform the duty otherwise the State must bear international responsibility. The judiciary as an organ of the State is accordingly obliged to fulfill the obligation. This article is aimed to examine an application of international law in Thai domestic legal system of Thai judicial practice, in context of a failure to comply with international obligations. It focuses only on the application of customary international law and treaty.

After doing the research, it appears that Thai judiciary has followed a strict dualist approach towards the application of international law. By which Thai judiciary is obliged itself by strict application of Thai laws regardless of international obligations. While, foreign judiciaries including Federal Republic of Germany, Republic of South Africa, and Canada strictly obliged themselves to follow neither monism nor dualism. They apply the law in their domestic legal systems in accordance with international obligations by way of a direct application of customary international law and a use of treaty to interpret the domestic law.

In consequence, it is here suggested that 1) There should be a broader interpretation of the powers of the Courts as entitled in Section 188 paragraph 1 of The Constitution of Thailand B.E. 2560. Where the definition of the “laws” in this Section should also cover customary international law; 2) The Constitution of Thailand should be amended to expressly incorpo rate customary international law as part of the law of Thailand in order to justify the judiciary in applying customary international law directly and legitimately; and 3) The judiciary should use a juristic method by applying and interpreting national law in conformity with international obligations.