The military enforces confidentiality in pre-sentencing witness interviews primarily through the rules of professional ethics that bind the attorneys and through the instructions given to the witnesses themselves. After a conviction but before the sentencing hearing, both the prosecution and the defense will interview witnesses who may testify during the sentencing phase. These interviews are a standard part of trial preparation.
For the defense, the interviews with potential mitigation witnesses are covered by the attorney work product doctrine. The defense attorney’s notes and impressions from these interviews are generally not discoverable by the prosecution. The attorney will advise their own witnesses not to discuss their upcoming testimony with anyone else. For the prosecution, their interviews with aggravation witnesses are also part of their trial preparation, and their notes are also generally protected work product.
However, the most important enforcement mechanism is the potential for charges if confidentiality is breached in a way that obstructs justice. If either party, or a witness, attempts to use information from these interviews to intimidate another witness or to improperly influence the outcome of the sentencing, they could be charged with obstruction of justice under Article 131b, UCMJ. While there is no formal “confidentiality” shield over the interviews themselves, the rules of ethics and the UCMJ provide a strong deterrent against misuse of the information.