(1)(a) Except as provided in paragraph (b), the judge presiding at the trial of an action is not competent to testify as a witness in that trial. An objection is not necessary to preserve the point.
(b) By agreement of the parties, the trial judge may give evidence on a purely formal matter to facilitate the trial of the action.
(2)(a) A member of the jury is not competent to testify as a witness in a trial when he or she is sitting as a juror. If the juror is called to testify, the opposing party shall be given an opportunity to object out of the presence of the jury.
(b) Upon an inquiry into the validity of a verdict or indictment, a juror is not competent to testify as to any matter which essentially inheres in the verdict or indictment.
The Judge as a Witness:
To preserve the neutrality of the court, a judge presiding over a trial is automatically incompetent to testify as a witness in that same trial. This error is so fundamental that an attorney does not even need to object to preserve the issue for an appeal. The only narrow exception is if all parties agree to allow the judge to testify about a purely formal matter to help move the trial along.
A Juror as a Witness:
This section contains two separate rules regarding jurors:
- During Trial: A member of a jury cannot be called to testify as a witness in the very trial they are serving on. This prevents the impossible situation where other jurors would have to weigh the credibility of one of their own.
- After a Verdict (The "Juror Shield"): After a verdict has been rendered, a juror cannot testify about what occurred during deliberations. This includes discussions, thoughts, motives, or any mental processes that led to the verdict. This rule protects the finality of verdicts and ensures that jurors can deliberate freely without fear of being cross-examined later about their thought process.
