The Sixth Amendment guarantees defendants in all criminal prosecutions the right to the assistance of counsel.' The right to counsel is essential to the working of the criminal justice system, as the attorney must present the defendant's case and provide guidance throughout the State's proceedings against the defendant. Indeed, "[tihe very premise of our adversary system of criminal justice is that partisan advocacy on both sides of a case will best promote the ultimate objective that the guilty be convicted and the innocent go free."
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