Tax Treaty Override and Pacta Sunt Servanda: The Italian Perspective

The purpose of this article is to show that, based on the Italian experience, tax treaty overrides should be prevented on the basis of both current law (international law remedies and domestic law) and economic theory. From the perspective of the current law, it is argued that the pacta sunt servanda principle is not only customary international law but also derives from treaties: it is implicit in the signing of a treaty that the Contracting States mutually undertake the obligation to apply the treaty provisions. Moreover, domestic law should be used as a way of preventing violations of international law, by adopting domestic constitutional mechanisms that prevent such violations. From the perspective of economic theory, breach of a tax treaty does not seem to be any more efficient than performance under that treaty, because of the long-term costs of breach, given the possibility of a general denial of the existence of the international legal order and the international tax regime.