Someone was shot in Chicago every 150 minutes during the first five months of 2016. Someone was murdered every 14 hours, and the city saw nearly 1,400 nonfatal shootings and 240 fatalities from gunfire. Over Memorial Day weekend, 69 people were shot, nearly one an hour, topping the previous year’s tally of 53 shootings. The violence is spilling from the Chicago’s gang-infested South and West Sides into the business district downtown. Lake Shore Drive has seen drive-by shootings and robberies.

The growing mayhem is the result...