The Single Tax Principle: Fiction or Reality in a Non-Comprehensive International Tax Regime?

It is possible to talk about an international tax regime taking into account the international regime theory developed in the framework of international relations. As this is defined as a set of rules and principles that regulate the international tax arena, this contribution analyses if the single tax principle can inspire such an international tax realm. The author explores the roots and developments of the single tax principle and focuses on the purposes of double tax conventions in order to determine whether single taxation is actually a desired outcome of tax treaties. The author also tackles international custom and arrives at the conclusion that the international tax regime does not rise to the level of customary international law. In this regard, the international tax regime is based on competition rather than on coordination, being regarded as a non-comprehensive regime. The question that arises, then, is whether single taxation can act as a coordination mechanism to turn the international tax regime into a comprehensive one.