Key points
Europe should assume that American readiness to use force in its defense will vary by crisis and depend on future American leadership, and the perceived escalation risk.
- European states should build the capability to deter and, if necessary, defend against aggression in the opening phase of a conflict without relying on immediate U.S. intervention.
- Europe should seek to assume the Supreme Allied Commander Europe (SACEUR) position as part of a broader rebalancing of alliance roles, aligning leadership with Europe’s growing responsibility while preserving
the U.S. role in nuclear deterrence and strategic enablers.
- Europeans should move from fragmented national procurement toward sustained production, stockpiling, and surge capacity, particularly in munitions, air and missile defense, long-range fires, drones, and sustainment through both the EU and cooperative projects involving interested states.
- European governments should improve their ability to decide and act quickly in a crisis, recognizing that unity lowers escalation risk and makes U.S. involvement more likely. They can do so in part through the mechanisms of the EU, but you should be willing to use other institutional and ad-hoc formats.
- A Europe that can act credibly on its own reduces the risks and costs of U.S. engagement, making American action more politically and strategically sustainable almost regardless of developments in the United States.
Full info
ARENA Policy Brief 2/2026 (pdf)
The Limits of Commitment: Four U.S. Defence Futures and the Meaning of Europe’s Security Guarantees
January 2026