In A Few Good Men, there’s some dialogue to the effect that defense counsel in a court-martial could be subjected to military discipline if he calls a commanding officer as a witness but that testimony doesn’t lead to an acquittal. (Of course, in true Hollywood style, Jack Nicholson’s snarling on cross-examination ends up making all the difference for Tom Cruise’s clients).
Is that an actual rule or DoD policy, written or unwritten? Sounds a bit odd to me, as well as a disincentive for defense counsel to zealously represent a client by going wherever the evidence leads him or her.