Why are Miranda warnings given?

They are an integral part of police arrest procedure, and were staple scripted fare on the Dragnet program. They include the right to remain silent, and the counter-argument that anything you say can and will be held against you in a court of law- the right to the presence of an attorney, and if you so desire and cannot afford one, an attorney will be appointed free of charge ( the last part involves the office of the Public defender, to provide legal council for those who cannot afford it). The officer then asks the suspect if he understands each of these rights and warnings- then Dumm Da Dumm Dumm- the arrest is official. the right to one free phone call is sometimes included in the drill! ( this was not used in Dragnet, as I recall.