Brandon Johnson vowed to drop controversial gunshot detection system but approved a $10m payment for contractor ShotSpotter

Progressives have vowed to hold the new Chicago mayor, Brandon Johnson, to his campaign pledge that as part of crime-control efforts in the city he will break with the controversial gunshot detection contractor ShotSpotter.

Johnson gave the keynote speech this week at Netroots, the largest annual gathering of progressives in the country, taking place in Chicago, and amplified his campaign talk about a wider approach to safer streets.