NATO–EU Strategic Priority: Forward Defence & Eastern Flank Deterrence

For NATO and its partners, “Forward Defence & Eastern Flank Deterrence” arose as a direct response to Russia’s aggressive revisionism and the radically altered European security landscape after 2014 and especially 2022. Russia’s full-scale invasion of Ukraine in 2022 shattered post-Cold War assumptions and confirmed that Moscow is “the most significant and direct threat to Allies’ security and to peace and stability in the Euro-Atlantic area” [1] . NATO’s 2022 Strategic Concept accordingly put deterrence and defence back at the core of Alliance strategy [2] [3] , re-embracing the logic of deterrence by denial : the Alliance must credibly demonstrate it can immediately thwart any incursion into Allied territory, rather than merely avenging it after the fact.

Eastern flank Allies – from the Baltic to the Black Sea – had long urged a shift from the symbolic “tripwire” presence of previous years to a robust forward defence posture. This priority was crystallised at NATO’s Madrid Summit in June 2022 and Vilnius Summit in July 2023, where leaders agreed on a “fundamental shift” to ensure the ability to “defend every inch” of Allied territory [4] [5] . Forward defence on the eastern flank is thus intended to deter a potential Russian attack by convincing Moscow that any aggression would be met with immediate, large-scale collective defence, denying the Kremlin any quick fait accompli.

This strategic priority is grounded in core political commitments of the NATO Alliance and supported by the European Union and national governments. The NATO Strategic Concept 2022 explicitly returned to the imperative of high-intensity collective defence against state aggression [2] , identifying Russia as a hostile power bent on revising the European order by force. The EU’s Strategic Compass 2022 likewise acknowledged a deteriorating threat environment in Europe’s East and stressed the Union’s role in reinforcing the security of its members and partners, in complementarity with NATO.