National leaders of the North Atlantic Treaty Organisation are gearing up for the alliance’s high-stakes summit next month in Lithuania. How has the war in Ukraine transformed Nato? And what comes next? Andrew Mueller speaks to Ingrida Simonyte, prime minister of Lithuania; Benedetta Berti-Alberti, head of policy planning in the Office of the Secretary-General at Nato; Kersti Kaljulaid, former president of Estonia; and Swedish political scientist Anna Wieslander.