‘No taxation without representation!’ It was the British Crown's attempt to tax tea that laid the groundwork for the American Revolution in the 18th century and, ultimately, the Declaration of Independence. This was neither the first nor the last example in history, but perhaps the most famous one to demonstrate the close connection between tax sovereignty and the civil nation state. Today, sovereignty in matters of taxation is still regarded as one of the core functions of the nation state. But is it still the nation state's own domain? This essay argues that, at least with respect to the European Union, the answer is no. It shows that the EU tax regime influences national policies in important ways, and imposes significant constraints on national tax sovereignty. It will also show that the lost sovereignty at the national level can be found again at the European level. Is it time to advocate a European Declaration of Dependence?