That is the opinion of Mr. Justice MacLean, in 4 MacLean's Circuit Court Reports, 103.
Mr. Merrick. If not improper I may remark that all those cases refer to a condition of things prior to the trial in which the party appears as the witness.
Mr. Ingersoll. The usual question is—and the court determines that question—whether a man shall be a witness or not.
The Court. How can the court determine that without passing upon the evidence in the case? That is not the duty of the court; it belongs to the jury.
Mr. Ingersoll. The prosecuting attorney has to pass upon that himself when he makes up his mind to put him upon the stand; and he only has the right to do that when he believes that no conviction can be had without that testimony.
The Court. Then it belongs to the prosecuting attorney.
Mr. Ingersoll. I go further than that, and say that the prosecuting attorney cannot do that without consultation with the court, and without saying to the court that he believes no conviction can be had without that testimony.
Mr. Merrick. May I be allowed to suggest a point which probably you would like to comment upon—that all these cases refer to accomplices prior to the trial. My own opinion in reference to the case was that I would not put Rerdell upon the stand until he had pleaded guilty.
The Court. I do not see the ground for the distinction between the cases. Undoubtedly, when an accomplice goes over to the Government and offers his testimony, he does it always in the hope of pardon or immunity from prosecution.
Mr. Ingersoll. That is all I want at present. I want it understood, if the Court please, that I shall argue to the jury that at the time he made up his mind to go to the Government, he understood that that meant immunity.