U.S. FOREIGN POLICY AS A CATALYST FOR EUROPEAN DEFENSE INTEGRATION (2012–2025)

This thesis investigates how and under what conditions U.S. foreign policy has acted as a catalyst for European Union defense integration between 2012 and 2025. It starts from the puzzle that major EU-level initiatives—including PESCO, the European Defence Fund, successive CARD/CDP cycles, and the Strategic Compass—coincide around moments of transatlantic tension rather than alignment. To explain this pattern, the study treats U.S. influence as three channels: alliance signaling (reassurance versus uncertainty about U.S. commitments), industrial dependence (asymmetries in arms sales, export controls, and defense markets), and threat prioritization (the evolving U.S. hierarchy of Russia and China). Using a structured-focused comparison of the Obama, Trump, and Biden presidencies, complemented by descriptive quantitative evidence, it looks at how these channels interacted with European threat perceptions, domestic politics, and institutional constraints. The thesis finds that U.S. foreign policy was neither the main driver nor irrelevant to Europe’s integration efforts. Instead, waves of negative or ambiguous signaling, industrial frictions, and a gradual U.S. shift toward the Indo-Pacific reduced political obstacles to EU-level defense initiatives, whereas periods of strong reassurance and manageable dependence tended to reinforce NATO and nationally centered solutions. In this way, the study offers a more precise contribution to debates on alliance politics, interdependence, and European integration.