At this point, we must turn from competence to power. Indeed, whereas competence is essentially a binary question, the legal framework within which an entity could make use of that competence, delineates its legal power (see supra page 12). For tax treaty-making, this means setting the legal framework within which the federal and component states can actually, given the current legal context, levy taxes and conclude treaties about those taxes.

FACING REALITY

When establishing theoretical frameworks and benchmarks one must keep in mind certain realities to avoid that they remain nothing more than an exciting, but nonetheless Utopian figment. For them to be functional, the practical limitations and constraints stemming from the current (legal) realities that govern present day international tax law and tax treaty-making processes must be recognized. After all, the very existence of representative democracy as the pinnacle of modern-day democracy is in itself already an inescapable concession from the ideal of the law's addressee who is also its author.

In this section, the current legal framework within which (in particular) tax treaties must be negotiated and concluded is addressed; especially from a Belgian point of view, as the Belgian example is at present the only one which adheres to the in foro interno et in foro externo principle.

The VCLT does not add much to the legitimacy of treaties. Indeed, where it provides that ‘every state possesses capacity to conclude treaties’, it has led authors to argue that only Westphalian states can conclude treaties. It has been pointed out that this is not the case, but that it merely means that the VCLT itself only covers treaties concluded by ‘states’ as defined under the VCLT, and that this term can arguably include component states as well. International law does not dictate which entity of a federation is to conclude treaties, but it does accept a renvoi to domestic legislation in this regard. If the federal constitution confers on component states the competence to conclude treaties, then this is accepted under international law. It does not, however, compel other actors to actually conclude treaties with them (supra).