Alaska Comm. R. Evid. 605
This rule eliminates the possibility that a judge who is presiding at a trial may be called to testify at the same trial. There are two concerns underlying this provision.
The first concern is largely a pragmatic one focusing on the procedural questions that would be likely to arise when the judge abandons the bench for the witness stand.
The second concern involves the potential prejudice to the party against whom the presiding judge testifies in that the jury may believe that the judge is aligned with the party helped by his testimony. The possibility that the jury may perceive partiality on the part of a judge is of sufficient magnitude to prohibit any judicial comment on the evidence. The possibility of unfairness when the judge is a witness also is sufficient to require a broad rule to control behavior. See Report of the Special Committee on the Propriety of Judges Appearing as Witnesses, 36 A.B.A.J. 630 (1950); Annot., 157 A.L.R. 311 (1945).
Nothing in this rule prevents a judge from testifying at a trial or proceeding at which he is not the presiding judge. For example, the trial judge is sometimes called to testify about the events of an earlier trial in a habeas corpus proceeding. This is especially necessary where the attack on the conviction comes in the form of an attack on the actions or motives of the trial judge. The danger of prejudice largely disappears where a trial judge testifies at a collateral proceeding since another jurist presides.
The second sentence of the rule indicates the importance of this incompetency rule. No objection need be made in order to preserve the point. In part, this stems from the belief that an immediate objection raised against the trial judge who decides to testify may prejudice the objecting party's chances of obtaining a fair trial. This follows New Jersey's Rule 42 rather than Uniform Rule 42 as promulgated in 1953, which prevented a judge from simultaneously testifying and presiding only if a party objected. The wisdom of disqualifying the presiding judge is so apparent, the likelihood of inadvertent judicial error is so low, and the dilemma facing the attorney who would like to object to testimony by the presiding officer is so real, that no violations of this rule will be tolerated.
Alaska Comm. R. Evid. 605