Since 2006, the Inter-American Court of Human Rights (IACtHR) has developed the “Conventionality Control”doctrine. Similar to “Constitutional Review”, which seeks to establish the prevalence of the Constitution of each state over other domestic rules, the conventionality control doctrine aims to strengthen the supremacy of human rights treaties over domestic law – constitutions included – of the states parties to them.

Currently, the doctrine has an impact on local judges and public authorities at all governmental levels, constraining them to perform ex officio a normative assessment of domestic rules according to the American Convention on Human Rights (ACHR). To perform that assessment, the doctrine also grants constraining power to IACtHR jurisprudence. As a result, not only would its jurisprudence be considered as binding to the parties to a specific case, but also for all the state parties to the ACHR, tantamount to having erga omnes effect and a ‘stare decisis et quieta non muovere’ rule, nonexistent in the Inter-American System. This is the most polemic issue: to go beyond res judicata to affirm the res interpretata of its decisions.

The principal arguments to support that are as follows: the ACHR outlines state obligations to develop practices to guarantee conventional rights (articles 1.1 & 2), thus national laws must be interpreted accordingly. Furthermore, the ACHR requires that states enable the most extensive enjoyment of rights “by effecting the most favorable interpretation of laws” (art. 29). These state duties are also reinforced “by the principles of good faith, effectiveness, and pacta sunt servanda, as well as by a judicial ban on drawing on domestic law as a means to justify failure to comply with treaties” (articles 26&27-VCLT).

In that context, current critiques of the conventionality control doctrine focus mainly on two aspects: (i) theoretical inconsistencies, and (ii) the probable risk/effect on the rule of law and constitutional democracies. This post will address the first one.

Our main argument is that the IACtHR, and favorable scholars, fail to provide a coherent theoretical basis for the res interpretata of its jurisprudence. This doctrine is not provided in the text of the ACHR or any other international law instrument; it has been exclusively derived from the interpretation of articles 1.1, 2 and 29 of the ACHR. Indeed, to adopt “other measures” (articles 1.1 & 2) for guaranteeing conventional rights, national authorities must interpret domestic laws according to the ACHR and considering the IACtHR’s interpretation thereof. Nevertheless, to assert the merits of the IACtHR jurisprudence should not automatically lead to equating its effects with those of the ACHR (a treaty), as these are two different sources of international law (art. 38-SICJ). Otherwise, through each new decision, the IACtHR would have the power to modify the ACHR’s provisions without any State participation. Certainly, each state might assign to the IACtHR jurisprudence a higher impact on its domestic law. However, that decision belongs to the states. For now, the only legal source that supports this doctrine is the IACtHR jurisprudence itself. Hence, an inevitable petitio principii arises: IACtHR jurisprudence is binding and has erga omnes effects just because IACtHR jurisprudence says so.

Furthermore, the usual appeal to general principles of law such as effet utile, pacta sunt servanda, good faith and pro homine, is hardly useful to strengthen the IACtHR’s position. Those propositions don’t answer the key question: why should the IACtHR’s decisions be considered res interpretata. Instead, such an appeal could strengthen ours. If the ACHR is binding and must be performed in bona fide (art. 26-VCLT), then States must comply with the judgment “in any case to which they are parties” (art. 68-ACHR). They have no erga omneseffects. Likewise, if the pro homine principle recognizes that the most favorable enjoyment of rights may come from state law or other treaties (art. 29-ACHR), then it is possible to prefer them if they are more protective than the IACtHR jurisprudence. There is not a binding jurisprudence or a failure in complying with a treaty, based on IACtHR jurisprudence (art. 27-VCLT). It seems there are not strong enough legal arguments to support the IACtHR’s doctrine, nor a favorable context for some state parties to accept it. The recent declaration of five states has reasonably called the IACHR and the IACtHR to respect the subsidiarity principle and their constitutional law, as well as to recognize a margin of appreciation, and to strictly apply the sources of public international law in its cases. Self-restraint and real dialogue could be better than more intervention (Conventionality Control) if we want to strengthen the Inter-American System.