The law of treaties before domestic courts

This paper does not aim to reiterate the law of treaties as such. Rather, we focus on how the law of treaties is used and applied in domestic courts -- a continuously relevant perspective as a growing body of substantive international rules and norms is enshrined in treaties (‘treaty law’), with normative effect in domestic legal orders.

Domestic courts may be faced with the entire range of rules codified in the 1969 and 1986 Vienna Conventions on the Law of Treaties. Judging from an inventory of case based on the ILDC database, however, it seems that certain questions are especially urgent: such as those regarding consent, entry into force, termination, interpretation and self-executingness of treaties. The sections in the paper generally correspond to themes and stages in the ‘life of a treaty’ which play a role in domestic case law: conclusion and entry into force (2); self-executingness (3); binding force and observance (4); reservations and declarations (5); interpretation (6); scope (7); successive treaties (8); amendment and modification (9); and termination and suspension (10).

A central feature of the treatment of law of treaties questions in domestic case law is the interaction (and occasional confusion) between the domestic and international law level. This interaction often adds a particular dimension to the legal questions addressed by national courts -- such as when the domestic approval and the international expression of consent are combined to appraise the conclusion of a treaty, or when the normative scope of the international rule as such is linked to domestic law rules for incorporation to appraise its applicability in domestic law.