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The European Union (EU) project of combining a single market with a common currency was incomplete from its inception. This article shows that the incompleteness of the governance architecture of Europe’s Economic and Monetary Union (EMU) was both a cause of the euro crisis and a characteristic pattern of the policy responses to the crisis. We develop a “failing forward” argument to explain the dynamics of European integration using recent experience in the eurozone as an illustration: Intergovernmental bargaining leads to incompleteness because it forces states with diverse preferences to settle on lowest common denominator solutions. Incompleteness then unleashes forces that lead to crisis. Member states respond by again agreeing to lowest common denominator solutions, which address the crisis and lead to deeper integration. To date, this sequential cycle of piecemeal reform, followed by policy failure, followed by further reform, has managed to sustain both the European project and the common currency. However, this approach entails clear risks. Economically, the policy failures engendered by this incremental approach to the construction of EMU have been catastrophic for the citizens of many crisis-plagued member states.