Comparison of Roles of California DUI Defense Lawyer vs. DUI Prosecuting Attorney & Police

Courts have noted there are rules of ethics that the California DUI defense attorney is bound by. However, his role and obligations are distinctly different than that of a California DUI prosecuting attorney. This distinction is aptly described as follows:

California DUI law enforcement officers have the obligation to convict the guilty and (ethically) to make sure they do not convict the innocent person charged with a California DUI. They must (ideally) be dedicated to making the criminal trial a procedure for the ascertainment of the true facts surrounding the commission of the California DUI crime.

To this extent, our so-called adversary system is not (theoreticaly) adversary at all; nor should it be. (Note in reality, this is not necessarily an ethical, theoretical or ideal world, though.)
But California DUI defense attorneys have no comparable obligation to ascertain or present the truth. Our system assigns a California DUI defense lawyer a different mission.

The California DUI defense attorney must be and is interested in preventing the conviction of the innocent, but, absent a voluntary plea of guilty, we also insist that he defend his client whether he is innocent or guilty.
The State has the obligation to present the California DUI evidence. California DUI defense lawyers need present nothing, even if he knows what the truth is.

California DUI defense attorneys need not furnish any witnesses to the police, or reveal any confidences of his client, or furnish any other information to help the prosecution’s case.
If a California DUI attorney can confuse a witness, even a truthful one, or make him appear at a disadvantage, unsure or indecisive, that will be his normal course. Our interest in not convicting the innocent permits counsel to put the State to its proof, to put the State’s California DUI case in the worst possible light, regardless of what he thinks or knows to be the truth.

Undoubtedly there are some limits which California DUI defense attorneys must observe but more often than not, California DUI defense lawyers will cross-examine a prosecution witness, and impeach him if he can, even if he thinks the witness is telling the truth, just as he will attempt to destroy a witness who he thinks is lying. In this respect, as part of our modified adversary system and as part of the duty imposed on the most honorable California DUI defense attorney, we countenance or require conduct which in many instances has little, if any, relation to the search for truth.

[(modified from) U.S. v. Wade (1967) 388 U.S. 218, 256-258 (Justice White, joined by Justice Harlan and Justice Stewart, dissenting in part and concurring in part).]