This paper examines the actions of the European Council during the Eurozone crisis through the lens of political constitutionalism. This analysis examines the role of political inputs in shaping EU constitutional developments, whether supranational or intergovernmental, to demonstrate the “legitimacy paradox” of new intergovernmentalism. That is, the European Council claimed the electoral legitimacy to rescue the Euro, but in doing so opened up new avenues for contesting EU legitimacy, notably in relation to national budgetary decision-making. For unlike with supranational constitutional agency, the European Council has the means to politicize its actions. However, the strategy taken during the sovereign debt crisis is shown to be one of depoliticization to prevent domestic contestation of EMU reform. At the same time, paradoxically, the politics of macro-economic policy has become Europeanized with the active participation of EU supranational actors. Since EMU reform is dependent on supranational enforcement of EMU rules, the new intergovernmentalism faces political contestation that previous, supranational EU constitutional development did not.