Ever closer or lost at sea? Scenarios for the future of transatlantic relations

•The rise of populism casts doubts on the future of EU-US cooperation.•Transatlantic relations will be shaped by five key drivers.•Liberal culture and EU members’ collective action capacity are most important.•Four scenarios illustrate potential futures for the EU-US relationship. Five key drivers will shape the future of transatlantic relations in the next decade. Generally, the extent of shared liberal culture and European collective action capacity are crucial for cooperation between the EU and US. Additionally, it matters whether policymakers on both sides of the Atlantic agree on a conception of global order, on how to handle future technologies, and on the use of military force. Building on these drivers we develop and discuss four scenarios. The first describes a world of selective cooperation as the EU disintegrates. In the second, the US withdraws from the global stage and Europeans are forced to assume a leadership position. The third depicts negative consequences from populist nationalism, reducing transatlantic cooperation to military action against perceived Islamist threats. In the fourth scenario we focus on future technology that threatens to overwhelm transatlantic regulatory capacity.