Zohran Mamdani has promised to transform New York City government when he becomes mayor. Can he do it? Mamdani, a 34-year-old democratic socialist, already faces intense scrutiny, even before taking office in one of the country's most scrutinised political jobs. Republicans have cast him as a liberal boogeyman. Some of his fellow Democrats have deemed him too far left. Progressives are closely watching for any signs of him shifting toward the center. On Jan. 1, he will assume control of America's biggest city under that harsh spotlight, with the country watching to see if he can pull off the big...