Prosecutorial discretion generally refers to the authority of a prosecuting officer or agency (United States Attorney or state District Attorney) to decide what if any criminal charges to bring against a person or persons, and what punishment or sentence to seek. Prosecutorial discretion may also be used by a police officer, for example, in deciding whether to issue a driver a speeding citation (ticket) or a warning.
Prosecutors generally have broad authority to make such decisions—subject to the right of the citizens to remove them from office, directly or indirectly, in the voting or election process.