United States v. Wade, 388 U.S. 218, 256 (1967)
"LAW ENFORCEMENT OFFICERS have the obligation to convict the guilty and to make sure they do not convict the innocent. They must be dedicated to making the criminal trial a procedure for the ascertainment of the true facts surrounding the commission of the crime...
But DEFENSE counsel has NO comparable OBLIGATION to ascertain or present the TRUTH. Our system assigns him a different mission. He 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 guilty or innocent...If he can CONFUSE a witness, EVEN A TRUTHFUL ONE, or make him appear at a disadvantage, unsure or indecisive, that will be his normal course.
...as part of our adversary system and as part of the duty imposed on the most honorable DEFENSE counsel, we countenance or require conduct which, in many instances, has little, if any, relation to the search for truth."
