The right to counsel in criminal prosecutions is guaranteed by the Sixth Amendment, which states that “in all criminal prosecutions, the accused shall enjoy the right … to have the Assistance of Counsel for his defense.” Although generally associated with trial, the right to counsel has been interpreted to apply to “every critical stage” of the criminal proceeding. Some encounters with the police are considered a critical stage of an investigation and therefore require the presence of a lawyer if the evidence obtained is to be admissible in court. The important cases briefed in this chapter on the right to counsel related to policing are Massiah v. United States and United States v. Henry.