The best way to discover the truth, according to the adversary model of criminal justice, is by having an advocate for the prosecution and for the defense. Each advocate has the responsibility for presenting the facts from a partisan point of view. This system is supposed to maximize the chances that all the relevant facts and arguments will be placed before a fact‐finder.
The Adversary Justice System
An important difference between the prosecution and the defense is that the prosecutor plays the double role of government lawyer and government representative, whereas the defense attorney acts primarily as the protector of the defendant's interests. These role differences produce divergent ethical responsibilities. As a matter of fundamental fairness, a prosecutor is obligated to turn over factual evidence that is favorable to the defendant when the evidence is material to guilt or punishment. The role of the defense attorney requires, however, that the attorney withhold truthful and relevant information from the court in a specific case—even though such a practice frustrates the search for the truth.
The attorney-client privilege in a criminal case
The general rule is that lawyer‐client communications are privileged, or confidential. Lawyers can't reveal a client's oral or written statements to anyone. If this sacred trust of confidentiality were not inviolable, a client wouldn't feel free to disclose to his or her attorney everything the attorney needs to know to represent the client's interests. If this privilege were abolished, great injury would be done to the adversary system of fact‐finding because clients would be afraid to confide in their attorneys.
Defense counsel justification for representing a guilty defendant
Defense lawyers are ethically bound to represent all clients — even those they know are guilty. Justice in the United States requires a vigorous defense to protect the innocent and to ensure that judges and citizens, not the police, determine whether the defendant is guilty of a crime. Some defense attorneys never ask their clients if they are guilty. They prefer to use the facts to focus on the government's failure to prove its case beyond a reasonable doubt and to leave to the judge or jury the question of guilt. The distinction between actual guilt and legal guilt is relevant here. There is a difference between what the defendant did and what the prosecution can prove. Regardless of what the defendant has done, the burden of proof is on the prosecution. Until the prosecution puts on enough evidence to convince a judge or jury that the defendant is guilty beyond a reasonable doubt, the defendant is not legally guilty.
Functions of the defense lawyer
The essence of the role of defense lawyer is speaking and acting on behalf of defendants. The defense attorney is central to the fair operation of the criminal justice process. The defendant needs assistance of counsel at every stage of the criminal courts process. While representing defendants, defense attorneys perform the following functions:
Represent the accused after arrest to give advice during police questioning and make sure constitutional rights are not violated during pretrial procedures.
Investigate details of the offense on behalf of the accused.
Discuss the case with the prosecutor to determine the strength of the prosecution's case.
Represent the accused at bail hearings and hearings on pretrial motions.
Negotiate deals with prosecutors, usually involving reduced charges and lighter sentences.
Devise a defense strategy.
Represent the accused at trial.
Design sentencing proposals that serve as alternatives to those recommended by prosecutors and/or probation officers.
Present an appeal.