On a mild spring night in Chicago, a woman told her 18-year-old boyfriend she wanted money for a barbecue. He rounded up three teenage friends, each with a long criminal record, and, according to prosecutors, they donned masks, carried guns, and robbed four people, tossing two to the ground. They went searching for more victims in a stolen Kia; shortly after 1:30 a.m. they crossed paths with Aréanah Preston.

Preston, a police officer, had finished her shift and, still in uniform, parked across the street from her family home on the South Side. The 24-year-old was to receive a master’s degree in law the following week. The police department viewed her as a future leader; the FBI had talked with her about a job. The young men in the Kia saw her as a target. They ran at her; a grainy security video shows muzzle flashes. Police and prosecutors say that at least two of the teenagers shot at Preston, who returned fire but was struck in the face and neck. One of the young men grabbed her firearm, and they fled.

Preston’s mother, Dionne Mhoon, had been out with friends in the suburbs and arrived home to patrol cars and swirling red lights. An officer drove her, praying, to the University of Chicago hospital. In a private waiting room, a door opened, and the mayor and a trauma surgeon walked in. We’re so sorry. We did all that we could. She was so brave, your daughter. Mhoon felt ruin. “I had poured so much love into her,” she told me in late September, as we sat in her office on Chicago’s South Side, where she runs a day care. She grew up and raised her daughters there. “It was unreal. I never expected this outcome, never. I don’t know what to make of this city.”

The story of this accomplished young Black woman slain in front of her family’s home gripped me when I first read of it. Preston died in May 2023, but her killing remains a powerful symbol of Chicago’s inability to solve its decades-long violent-crime problem. Mhoon and her daughter tried to ward off the violence around them but still couldn’t avoid it. And Preston’s own department failed her: The ShotSpotter sensor technology the city used marked the sound of eight shots and relayed the address to police dispatchers. Preston’s smartwatch alerted dispatchers to what it detected as a “car crash” and also conveyed the address. Yet, on a busy night for the police, 31 minutes passed before an officer arrived and found Preston lying on the sidewalk. (The police department launched an investigation into the response time. I asked a spokesperson about the status but didn’t get an answer by publication time.)

Preston’s killing was particularly high-profile, but among America’s cities with populations of more than 1 million, Chicago has, for decades, had among the highest rates of homicide. President Donald Trump has seized crudely upon this misfortune and recently described the city as a “killing field.” He has mocked the mayor, Brandon Johnson, and Illinois Governor J. B. Pritzker, and earlier this month he sent 500 National Guard troops to the Chicago area declaring that Johnson and Pritzker “should be in jail.” (Courts have temporarily blocked troops from deploying in the city.)

Taylor Glascock for The Atlantic Dionne Mhoon, the mother of Aréanah Preston, started a foundation in honor of her daughter.

Democratic politicians have taken the president’s bait. Chicago, they argue, is not as violent as it once was. Crime in some cities in Republican-run states is worse, and red-state gun stores sell many of the weapons that Chicago men slip into their belts and hoodies. Pritzker, who has said that Trump’s threats against the city suggest that he has dementia, took a walk last month along the Chicago lakefront with an NBC reporter.