What must a lawyer do if they discover the client intends to testify falsely?

When a lawyer discovers that a client intends to testify falsely, the lawyer has a fundamental ethical obligation to uphold the integrity of the legal process. The correct action is to refuse to introduce the false evidence. This stems from the duty of candor towards the tribunal, which requires lawyers to act truthfully and not to facilitate dishonesty in the courtroom.

If a lawyer were to support the client's false testimony or allow the testimony to happen without intervention, it could undermine the legal system and contribute to a miscarriage of justice. Lawyers also have a professional responsibility to maintain credibility with the court, and facilitating false testimony would severely compromise that.

The first option implies that the lawyer should actively support the deceit, which is directly contrary to ethical obligations. Similarly, letting the client make the decision without interference would allow dishonesty to enter the proceedings unchecked. Negotiating different testimony might seem plausible, but it does not address the core issue of preventing false evidence from being introduced. Therefore, the only ethically sound action in the face of potential false testimony is to refuse to introduce it, maintaining the commitment to truth and justice.