Luigi Mangione's case marks a shift in politics of the death penalty in the U.S. NPRLuigi Mangione pleads not guilty to federal charges in killing of UnitedHealthcare CEO CNNLuigi Mangione pleads not guilty in federal court to murdering healthcare CEO The GuardianLuigi Mangione pleads not guilty to federal charges in CEO killing Fox NewsLuigi Mangione live updates: Death penalty sought in UnitedHealthcare CEO shooting BBC