Final answer:
Miranda v. Arizona is the case that established the requirement for suspects to be informed of their rights, known as Miranda Rights, upon arrest to ensure due process and protection against self-incrimination and to guarantee the right to counsel.
Step-by-step explanation:
The case that expanded the rights of the accused by mandating that they be informed of their rights upon arrest is Miranda v. Arizona. The U.S. Supreme Court's 1966 landmark decision required that suspects be read a series of rights known as the Miranda Warning. These rights include the right to remain silent, that anything said can be used against them in court, the right to an attorney, and if they cannot afford one, the right to have an attorney provided. This case underscored the importance of due process and protections against self-incrimination under the Fifth Amendment and the right to counsel as guaranteed by the Sixth Amendment.