I am a taking a criminal justice class and just cant seem to put a an answer to this question:
If we believe that the purpose of the criminal justice process and the trail is to get at the truth (convict the guilty and acquit the innocent) why do we allow defense attorneys to remain quiet about the evidence that proves his client is guilty?
Can you please help me with this question if possible.
Our judicial system was created with a healthy amount of distrust for the government built in (after all, a lot of out founders were smugglers). Therefore, we did not set up the criminal justice system with an eye solely toward separating the guilty from the innocent. We set it up with a strong bias toward protecting the rights of citizens and particularly those accused of a crime.
There are a number of different protections built into the system which we take for granted: juries composed of citizens, double jeopardy protections, unanimous convictions, &cetera. If our system was only concerned with sorting guilty from innocent we could have set up a system wherein judges make all the decisions, the prosecution has the right to appeal improper trial court decisions and retry someone if the trial judge was wrong, and a conviction could occur if only 7 of 12 jurors (a simple majority) found the evidence sufficient. There is a clear bias toward the protection of the defendant.
Before I examine your specific concern, let me first lay out what I think a defense attorney must do and what he cannot do. A defense attorney has a duty not to disclose anything which occurs between the client and himself. However, there are exceptions to this. A defense attorney is obligated to report to the authorities any illegal act which the defendant tells him he will do in the future. A defense attorney cannot hold physical evidence which his client has given him - he must turn it over to the authorities unaltered; he doesn't have to tell them who gave it to him, but if he's representing only one axe murderer and he turns over a blood spattered axe they'll probably figure it out. As well, a defense attorney must not lie to the judge or jury. In other words, if the defendant has told his attorney that X happened the attorney cannot tell the judge or jury that Y happened; he may walk a fine line,asking officers why they didn't investigate Y and asking the jury why the officers didn't, but he cannot assert that Y happened. It's the difference between asserting that law enforcement and the prosecution have failed to prove their case by eliminating all reasonable doubt and asserting a falsehood.
However, you are absolutely correct, a defense attorney has an obligation to sit on his hands and say nothing if he knows something which will undoubtedly prove his client guilty but the prosecution doesn't. This is part of the protections offered to citizens against the government. I think the strongest argument is probably rooted in the 6th Amendment requirement that "[i]n all criminal prosecutions, the accused shall enjoy the right . . . to have the Assistance of Counsel for his defence." The constitutional duty of the defense counsel is toward the defendant, not the court or sorting out who is innocent/guilty. If the defendant cannot tell the defense attorney the truth because the defense attorney is going to disclose information which the defendant gives him that is indicative of guilt then the assistance of counsel which the defendant is constitutionally guaranteed is denied him. Basically, it would mean that many defendants would have their right to force the prosecution prove its case beyond a reasonable doubt denied them if they were honest with their attorney.