Under heavy grey skies and a thin coating of snow, hulking grey and green Cold War relics recall Ukraine’s Soviet past. Missiles, launchers and transporters stand as monuments to an era when Ukraine played a key role in the Soviet Union’s nuclear weapons programme - its ultimate line of defence. As a newly independent Ukraine emerged from under Moscow’s shadow in the early 1990s, Kyiv turned its back on nuclear weapons. But nearly three years after Russia’s full-scale invasion, and with no clear agreement among allies on how to guarantee Ukraine’s security when the war ends, many now feel that...