Europe’s New Security Architecture

How minilateral formats are reshaping the continent’s defence.

The accelerating proliferation of minilateral security formats is reshaping European defence — from Nordic-Baltic cooperation to the Joint Expeditionary Force. At the heart of it, the Weimar Triangle has the potential to provide the strategic coordination Europe urgently needs. The architecture that is emerging is more dynamic than it appears but has never been tested in a real crisis.

Something significant is happening in European security — and it is not happening inside NATO or the EU. Across the continent, a proliferation of flexible, issue-focused minilateral formats has emerged alongside the traditional institutional architecture. Some formats are old and have been energised; others are brand new. Together, they are reshaping how Europe actually organises its defence.

The pattern has three defining features. First, a multiplying set of more or less permanent minilateral groupings, each serving distinct but overlapping purposes, cutting across the formal structures of NATO and the EU rather than nesting neatly inside them. Second, a thematic focus firmly on security and increasingly and more narrowly on defence, with varying emphasis on military, political, and economic dimensions. Third, a geographic logic centred on the Nordic and Baltic region, and along a north-south axis running from the Baltic to the Black Sea and the Adriatic.

The Weimar Triangle has the potential to provide strategic coordination across these different formats — but it has never been tested in a real crisis.

Two simultaneous pressures explain why this is happening now. The first is Russia: the full-scale invasion of Ukraine in 2022 and the sustained hybrid war being waged across Europe’s political and physical infrastructure. The second is the United States: a trajectory that runs from soft retrenchment through hard disengagement toward what some European governments now model as potential strategic exit — compounded by active interference in European political affairs and a broader assault on the international order Washington itself built in the decades after the end of the Second World War. Europe needs to manage both pressures at once, at a moment when domestic polarisation is rising, democratic institutions are under strain, and economies are underperforming.

Minilateral formats, and their proliferation, is the response — and potentially part of the solution.