The judge presiding at the trial may not testify in that trial as a witness.
This section states the first sentence of Fed. R. Evid. 605 and Proposed Mass. R. Evid. 605. While there are no Massachusetts statutes or cases on point, the proposition appears so clear as to be beyond question. See generally Supreme Judicial Court Rule 3:09, Canon 3(E) (judicial disqualification); Glenn v. Aiken, 409 Mass. 699, 703, 569 N.E.2d 783, 786 (1991) (“calling a judge as a witness to opine on what ruling he might have made on a particular hypothesis” is disfavored). Cf. Guardianship of Pollard, 54 Mass. App. Ct. 318, 322–323, 764 N.E.2d 935, 939 (2002) (judge who served as guardian ad litem prior to becoming judge not disqualified from testifying in guardianship proceeding before a different judge and from being cross-examined on her guardian ad litem report).