Prosecutors have the power to make decisions that have a deep impact on the lives of arrestees and defendants. This power arises, in large part, from the enormous discretion they exercise over decisions like whether to initiate charges and which charges to bring, whether to offer plea bargains and under what terms, what sentences to seek, and how to present and try a case. Public attention has focused on prosecutors’ discretion in recent years, as their conduct is increasingly scrutinized in high-profile cases involving civilian deaths in police shootings and sexual assault by wealthy, powerful men. Professors Bruce Green and Rebecca Roiphe, both former prosecutors, discuss through the lens of recent controversial cases the ethical and legal standards governing prosecutorial conduct and why prosecutorial discretion is not a black-and-white matter.