If Europe pivots towards military rearmament in the aftermath of the 2022 Russian invasion of Ukraine, it will be starting from a particularly low base. As the head of the German Bundeswehr angrily wrote on LinkedIn at the beginning of the crisis, the cupboard is bare.1 Europe’s overall military weakness is partially a result of integration with the U.S.-dominated North Atlantic Treaty Organization (NATO), where U.S. preferences for European states to maintain small, specialized, and interoperable militaries, that ultimately rely on the overwhelming might of the U.S. military as a guarantor of security, tend to win out against any attempts to develop the capability for unilateral military action.2 But even if NATO preferences were to reverse overnight, it is not clear that the institutional capacity to effectively reform, modernize, and expand European militaries is widely available. For many Western militaries, the first two decades of the 21st century were a difficult time, as the pressures of the war on terror caused budget cuts to conventional military capabilities and the delays or even cancellations of modernization programs. In the European Union (EU), military expenditure as a percentage of GDP continued a long trend of decline that began as far back as the 1960s.3