Determining hierarchy between conflicting treaties: are there vertical rules in the horizontal system?

Treaties are contractual instruments that may provide special rules of priority in case they conflict with other treaties. When a treaty does not provide such rules, however, priority is determined by the rules of the Vienna Convention on the Law of Treaties (VCLT) and/or general principles of law. This article argues that both the VCLT and general principles of law do not provide an adequate solution to treaty conflicts. It suggests that the solution to treaty conflicts rests in a value-oriented reading of international law and the norms incorporated in treaties. Norms represent values and values represent interests or benefits for which international society requires protection. Conflicts of treaty norms are, therefore, conflicts of values that courts and dispute settlement bodies resolve by ordering a hierarchy of competing interests and protecting the most important interests in a given context.