Only months after Donald Trump became the federal president in the U.S., an idea, “once unthinkable,” was “gaining attention in European policy circles: a European Union nuclear weapons program.” The arsenal in the state of France would be “repurposed”—which is to say, federalized in American terms—to protect the European Union rather than merely one of its states. The command of the weapons, as well as the funding plan and defense doctrine, would be federal. Even though the question of whether the E.U. could continue to count of American protection—there being dozens of American nuclear weapons in the E.U.—was at the time most tantalizing, I submit that the matter of federalism in the case of the E.U. is salient too.
Boderich Kiesewetter, a state lawmaker and foreign-policy spokesman with the ruling party in the E.U. state of Germany pointed to “four ingredients: a French pledge to commit its weapons to a common European defense, German financing to demonstrate the program’s collective nature, a joint command and a plan to place French warheads” in other states. The joint command and dispersion of the existing warheads are particularly important to the transfer of the program to the federal level, especially given the amount of sovereignty that the states still retained. This imbalance carries with it the risk of dissolution (rather than consolidation). Should the E.U. break up, the state of France would doubtlessly reclaim the warheads existing in the state. This possibility alone would give the state government an inordinate amount of sway at the federal level on the common defense. Put another way, the nuclear program really would have to be federalized, with built-in assurances that France’s government would not be able to have disproportionate sway.
In regard to whether such a program should be federalized, it is notable that defense has typically been among the first domains to be assigned to a federal government. Federalism itself came out of alliances historically—where a common defense and the regulation (i.e., protection) of internal commerce were the two main benefits. The E.U. would be more in line with federalism historically were defense federalized. To be sure, the states would and arguably should retain their own military forces, as is the case in the U.S., so the states have some means of defending themselves not against each other but, rather, from federal encroachment—for instance, an over-extended federal military. One of the chief benefits of federalism is that the states can provide on the federal government, and vice versa. A balance in terms of state-level and federal-level defense can serve as a subtle bedrock or foundation as against not only consolidation, but also too much state power at the expense of the whole. Because the latter excess was still the case in the E.U. when the proposal was being debated in 2017, the federalization of the nuclear deterrent has a lot going in its favor. In fact, the excess of state power—wherein the interests of particular states can too easily supersede the common good of the Union—would (other things equal) make the federalization more difficult than is optimal for the good of Europe itself. This itself is an argument in favor of the federalization. It is important to a federal system that the state and federal powers are in balance, as both the cultural and ideological diversity between states and the common good of the whole (i.e., the Union) are legitimate and warrant a sufficient buttress of power.
 Max Fisher, “Fearing U.S. Withdrawal, Europe Considers Its Own Nuclear Deterrent,” The New York Times, March 6, 2017.