The Ukraine war highlights the deep strategic folly of Euroscepticism

Rishi Sunak (L) and Volodymyr Zelenskiy in Hiroshima, Japan, May 2023. ‘Nato and the EU are two arms of the same embrace, but Sunak can only do continental strategy with one hand behind his back.’ Photograph: Anadolu Agency/Getty Images

Nato must protect Ukraine from Russian aggression, and also Ukraine cannot join Nato while it is at war with Russia. That is the conundrum that leaders of the western military alliance grapple with at their annual summit in Vilnius.

Kyiv craves the security of a mutual assistance pact – the ultimate solidarity that treats an attack on one Nato member as an aggression against them all. Nothing short of that guarantee, underwritten by US firepower, will persuade Russia to respect post-Soviet borders.