Focus is on the use of three legal techniques for subverting the truth: cross-examination of a truthful Government witness to undermine his or her testimony or credibility, direct presentation of testimony to discredit truthful evidence or accredit a false theory, and arguments to the jury based on any of these acts. While it is true that the prosecution has the burden of proving guilt and the defense attorney has the right and obligation to challenge the Government's proof to ensure its accuracy and to remain passive in the presentation of facts to the jury, the defense attorney does not have a duty or right to subvert the truth. Some have argued that attorneys cannot know the truth and therefore are free to present any available defense theory. However, lawyers are able to evaluate evidence and probabilities. Further, neither the right to a defense nor the needs of the adversary system, to arguments adduced for a truth-subverting role, justify the presentation of a false defense. A new rule of conduct is proposed that holds that it is improper for an attorney who knows beyond a reasonable doubt the truth of a fact established in the State's case, to attempt to refute that fact through argument or the introduction or impeachment of evidence. The attorney remains free to challenge State evidence, but more in the capacity of an officer of the court than as one vouching for the client's innocence. 119 footnotes.