The stipulation requiring that acussed persons be told they have the right to remain silent stems from

These rights, called the Miranda Rights, come from both the 5th amendment and a court case where a person named Miranda was let go after admitting to something he did because he argued that he was not aware that it was his right to remain silent. Now, when someone is being questioned by any law enforcement personnel, they must be read "You have the right to remain silent. Anything you say can and will be used against you in a court of law. You have the right to have an attorney present before or during this questioning. If you cannot afford an attorney, one will be provided to you at your request at no cost to you. Do you understand these rights?" 

An elector in the electoral college.