Leftwing Democrats are having their moment in the sun, with Zohran Mamdani in New York, Abdul El-Sayed in Michigan and endless calls for Alexandria Ocasio-Cortez to run for president in 2028. Has Democratic socialism shifted from the political fringe to the mainstream? And can this group lure back the all-important swing voters? Jonathan Freedland speaks to Bhaskar Sunkara, president of the Nation magazine, founding editor of Jacobin and author of The Socialist Manifesto: The Case for Radical Politics in an Era of Extreme Inequalities