After New York City’s race for mayor catapulted Zohran Mamdani from state assembly member into one of the world’s most prominent progressive voices, intense debate swirled over the ideas at the heart of his campaign. His critics and opponents painted pledges such as free bus service, universal childcare and rent freezes as unworkable, unrealistic and exorbitantly expensive. But some have hit back, highlighting the quirk of geography that underpins some of this view. “He promised things that Europeans take for granted, but Americans are told are impossible,” said the Dutch environmentalist and former government adviser Alexander Verbeek in the wake...