Shifting federalism? Comparing centralisation and decentralisation in EU and US governance since 2000

This article examines the evolution of centralisation and decentralisation trends in the EU and the US since 2000, exploring which factors explain variation in these trends and whether the two systems are converging towards a similar institutional equilibrium or diverging further. It builds on the hypothesis that both entities, which are both federal political systems, are constantly being shaped by major crises that influence the vertical balance of power within each system. The results reveal two distinct trajectories. The US exhibits an oscillatory federalism, characterised by sharp crisis-driven centralisation followed by decentralising reversals. By contrast, the EU follows a more stable but gradual path towards centralisation, punctuated by key moments such as the creation of NextGenerationEU, which constituted a Hamiltonian moment of supranational fiscal consolidation. While both systems have centralised in response to crises, their trajectories remain parallel rather than convergent, reflecting fundamentally different models of federal governance. Still, the EU may be slowly moving towards the kind of fiscal and political union that it took the US centuries to build.