The principle of legality of taxation has gained a supranational status by means of its transplantation out of the national setting to a general principle of EU law by the Court of Justice of the European Union (CJEU). In this article the two cases in which the Court has given a first supranational interpretation of the principle are discussed, as well as the Research Note the Court published before rendering its judgment in these two cases. This European translation contains an uncertainty as to the representative democratic elements of the principle that are closely connected to its historical development in several national legal contexts of Member States. With the European principle being rooted in the national legal orders of the Member States, this current discrepancy stands at odds with the material scope in several Member States, which ascribes clear democratic elements to the principle. Thus, the main question addressed after taking a look at the national interpretations and the representative democratic elements contained therein in the Netherlands, France, Italy and Germany, is if the omission of these democratic elements can prove to become an obstacle for future harmonization or integration in taxation. The focus will lie on the current mode of norm-creation in above-state settings and the creation of ‘genuine’ own resources for the EU.