Under international human rights law, the principle of subsidiarity presumes that States Parties to human rights treaties have the primary responsibilities of human rights protection and international treaty mechanisms complement domestic systems. State Parties - especially, domestic courts, independent from the legislative and executive branch - assume the primary role of controlling the compatibility of national law with human rights conventions (the conventionality control) as well as the constitutional norm-control (the constitutionality control). Nevertheless, the conventionality control is often disregarded under the strong political influence.
Against this background, the Inter-American and European Court of Human Rights (IACtHR/ECtHR) exercise the subsidiary norm-control in accordance with the American and European Convention on Human Rights (ACHR/ECHR). The Courts are authorized to develop the Conventions standards to be generally applied beyond the individual case (norm-developing function). Against this yardstick, these courts also conduct the judicial review of national acts and order specific remedial measures to bring domestic legal systems in line with these standards (judicial review function). With these functions the Courts behave as national constitutional courts to maintain the constitutional legal orders based on the Conventions (constitutionalization of international adjudication (Part I)).
In parallel to the international judicial control, there is a tendency that domestic courts reconcile the conventionality and constitutionality controls within the domestic legal orders. Actually, national judges have integrated human rights conventions into national constitutions in order to converge the parallel judicial controls. Moreover, some domestic courts utilize human rights conventions to decentralize the norm control authority from constitutional judges to all ordinary judges. These practices imply that the constitutionality control is substantively complemented by the conventionality control (internationalization of constitutional adjudication (Part II)).
Given these parallel phenomena, this project addresses the theoretical question of the relationship between international and domestic legal orders in terms of the conventionality control. Regarding the analytical framework, this research focuses on two elements (see Table 1): parameters under human rights conventions employed as the yardstick for the judicial review of domestic law (Chapter 1); and competences of human rights courts and domestic courts for the norm-control (Chapter 2).
The project includes both descriptive and normative analysis. Descriptive analysis examines the conventionality control exercised by the IACtHR/ECtHR and domestic courts of States Parties to the ACHR/ECHR. Normative analysis indicates two proposals for understanding the confluence between human rights conventions and national constitutions. First, parameters of the conventionality control are interpreted (Part I – Chapter 1) and applied (Part II – Chapter 1) in the light of the substantive contents which are favorable to individuals (the pro homine principle) rather than the formal hierarchy (the principle of supremacy of international law or constitution). Second, the competence to exercise the conventionality control are not concentrated in a single institution but diffused to human rights courts (Part I – Chapter 2) and all domestic courts including constitutional and ordinary judges (Part II – Chapter 2) in accordance with the principle of subsidiarity.