Except for a small number of diplomatic passports, there is no such thing as an EU passport. In practice, to be a citizen of the European Union means to be a citizen of one of the member states of the EU. It is the EU member states themselves which ultimately determine who is a citizen of the EU. As The Economist put it, "Deciding who is and is not a citizen is a jealously guarded right of EU member states."

The most rabid Europhiles—those who want to centralize political power under an EU state in Brussels—would be more than happy to abolish member-level citizenship altogether. Among many Europeans, though, there is a lingering reluctance to hand over powers of naturalization to the European ruling elite. There is good reason to be cautious. Centralizing the power to grant citizenship has long been important to state building, to consolidating political power, and to erasing allegiance to any political institution except the central state.

This centralization of authority over naturalization has helped expand state coercion through both social and political effects. For example, were the member states of the EU to abandon member-state control over citizenship, being a "citizen of Europe" would soon become far more important in everyday life than being a citizen of, say, Italy or Denmark. Transferring naturalization powers to Brussels would greatly accelerate the Europhile program of creating a European megastate under which places like Italy or Poland or Austria become mere administrative units.

That is, Europe would become like the United States where member-state power over citizenship is only nominal. In the US, citizenship within any particular member state carries very little psychological or political weight. In modern times, the only passport any American carries is a passport issued solely by the US government.