European leaders face an unprecedented challenge: building continental defence whilst managing an unpredictable American president.
Russia’s illegal annexation of Crimea and subsequent full-scale invasion of Ukraine has brought urgent pressure to rebuild European security. The dramatic shift in US foreign and security policies with Donald Trump’s return to the White House has intensified the burden on European governments to compensate for what has been America’s steadfast commitment to European safety for decades.
As NATO members gathered in The Hague for their summit on 24-25 June 2025, NATO remains the primary framework for European security, with America’s role in enabling the alliance still crucial. Europeans cannot yet defend themselves alone, even if they were willing to try. The declaration adopted in The Hague states the “ironclad commitment to collective defence as enshrined in Article 5 of the Washington Treaty”.
Yet given the profound and likely lasting reorientation of US policy towards Europe, Europeans would be wise to act decisively now. They must clear the path towards a continental security architecture that no longer depends on America.
The collapse of mutual trust between much of Europe and the Trump administration has made meaningful engagement extremely difficult on such an existential issue. US and European interests, long broadly aligned, have suddenly and sharply diverged—and will likely diverge further as rapid policy changes unfold in America, including challenges to democracy’s foundations.
Since taking office, Trump has openly sided with Putin on Ukraine, set his sights on Greenland, launched a trade war against allies, undermined international organisations and treaties, and supported Europe’s illiberal political forces.
A security alliance need not rest on the value base that has anchored NATO for decades. But especially during wartime in Europe, the unpredictable and potentially hostile nature of US policies carries enormous political risks for European leaders. Pure self-interest demands that Europeans begin shaping their continent’s security future.
Considerable thinking is already underway about reforming NATO and strengthening its European pillar. Christian Mölling and Thorben Schütz argued earlier this year that Europeans must manage the inevitable transatlantic divorce and build their own “European way of war”. Giuseppe Spatafora has outlined a roadmap for NATO reform in the Trump 2.0 era. Sven Biscop goes further, detailing what “thinking big”—a genuinely European security order without America—might look like.
These discussions are also happening in European and other like-minded capitals, though less visibly given current dependence on US security guarantees. The NATO summit in The Hague represented one crucial piece of this complex European security puzzle. As long as Europe remains vulnerable without America, Europeans must work to keep Washington engaged whilst hoping for US cooperation in their long-overdue strategic shift.
The focus on President Trump’s demand for five percent of GDP investment in defence serves this purpose. However unrealistic for many NATO members, however politically challenging it proves domestically—as Germany’s divisive SPD “manifesto” recently demonstrated—and however little it might impress Putin, this “big number” could prove a lifeline for Europeans transitioning towards rebuilding their continent’s security architecture.
The real work for European leaders begins now. Trump 2.0 may have jolted Europe into action, but it is Putin who fuels European leaders’ determination to protect their citizens in future.
Europe has attempted this before. Plans to organise European security through closer continental collaboration date back to European integration’s early days. The European Defence Community (EDC), signed by the six founding European Community members in 1952, never materialised after France’s National Assembly indefinitely postponed ratification in 1954, followed by Italy. The treaty would have established a defence community with joint supranational institutions, armed forces, and a common budget—complementary to NATO whilst strengthening the alliance’s European pillar.
Legally, as Federico Fabbrini argued in 2024, the EDC could be reactivated through new ratifications in French and Italian parliaments. Politically, however, significant challenges make this scenario unlikely to feature in current discussions about reorganising European security. Fundamentally, the EDC’s weakness in today’s context is its integration with NATO, assuming a strong and committed America as the key defence partner.
Today’s task for Europeans is far greater: they must prepare to conceptualise European security without America. The encouraging news is that Europeans possess the agency to achieve this—no small matter given Russia’s existential and immediate threat.
This is a joint column with IPS Journal
Almut Möller is Director for European and Global Affairs and head of the Europe in the World programme.