The government’s ability to use undisclosed rebuttal witnesses depends on several factors including the timing of disclosure, nature of testimony, and prejudice to the defense. RCM 701 requires prosecution disclosure of witnesses “before the beginning of trial on the merits,” but rebuttal witnesses responding to unexpected defense evidence may arise during trial. The key distinction is whether the government could have reasonably anticipated needing the witness based on known defense theories.
If the defense presents truly unexpected evidence or testimony, the government may call undisclosed rebuttal witnesses with the military judge’s permission. However, the prosecution cannot sandbag by withholding known witnesses hoping to use them in rebuttal. When the defense provides notice of defenses like alibi or mental responsibility, the government must disclose anticipated rebuttal witnesses during regular discovery.
Military judges balance several factors: whether the testimony is true rebuttal or improperly withheld case-in-chief evidence, the defense’s opportunity to prepare for cross-examination, and available remedies short of exclusion. Options include granting continuances for defense preparation, limiting testimony scope, or allowing surrebuttal witnesses. Exclusion typically occurs only for willful discovery violations or when no other remedy cures prejudice. The defense must object promptly and articulate specific prejudice from lack of notice. Pattern violations by trial counsel may warrant stronger remedies including dismissal of affected charges.