Yes. A military accused, through defense counsel, can move for a mistrial when the prosecution exposes the panel to inadmissible evidence. But asking for a mistrial and receiving one are very different things. The motion is governed by Rule for Courts-Martial 915, and the standard a military judge applies is demanding. Understanding how that rule works, and why judges rarely grant the relief, helps explain what actually happens when prejudicial material reaches court members in a court-martial.
The legal standard under RCM 915
Rule for Courts-Martial 915(a) allows the military judge to declare a mistrial when “manifestly necessary in the interest of justice because of circumstances arising during the proceedings which cast substantial doubt upon the fairness of the proceedings.” A defense request to inadmissible-evidence exposure falls squarely within that language, because evidence the panel was never supposed to hear can taint the fairness of deliberations.
The phrase “manifestly necessary” sets a high bar on purpose. Military appellate courts have repeatedly described a mistrial as a drastic remedy to be used with great caution, under urgent circumstances, and only for plain and obvious reasons. The reason is practical. A mistrial wastes the resources already invested in the proceeding, may delay justice for both sides, and in some situations can affect later double jeopardy questions. So even when inadmissible evidence reaches the members, the judge does not reach for a mistrial first.
Why a curative instruction usually comes first
The preferred remedy in military practice is a curative instruction rather than a mistrial. When a witness blurts out something inadmissible, or trial counsel references matter the judge has excluded, the defense can object and ask the judge to instruct the members to disregard what they heard. Military courts presume that members follow the instructions they are given. Because of that presumption, a properly worded instruction is often treated as sufficient to cure the prejudice.
A mistrial becomes appropriate only when the inadmissible matter is so prejudicial that no instruction could realistically remove it from the members’ minds. The classic examples involve disclosures that strike at the heart of the case: a reference to the accused’s prior convictions in a case where character was not in issue, an inadmissible confession, or a comment on the accused’s invocation of the right to remain silent. Even then, the judge weighs whether a tailored instruction can repair the damage before granting the more extreme relief.
What the defense should do procedurally
Timing and preservation matter. Defense counsel should object promptly when the inadmissible material surfaces, state the specific basis for the objection, and request relief on the record. Counsel can ask for a curative instruction, a strike, or, when the prejudice is severe, a mistrial. Articulating clearly why an instruction would be inadequate is essential, because the judge must consider lesser remedies before declaring a mistrial.
The defense should also be deliberate about whether it actually wants a mistrial. A mistrial can mean starting over with a new panel, which is not always to the accused’s advantage. Counsel sometimes prefers a strong curative instruction, or a different remedy such as excluding a witness or limiting argument, so the case proceeds before a panel counsel has already assessed rather than starting over before an unknown one.
The role of the military judge’s discretion
Whether to grant a mistrial rests within the sound discretion of the military judge, who is in the best position to evaluate the courtroom atmosphere, the manner in which the inadmissible matter came out, and its likely effect on the members. On appeal, that decision is reviewed for abuse of discretion, a deferential standard. An appellate court will not reverse simply because it might have weighed the prejudice differently.
This discretion cuts both ways. A judge who grants a mistrial without first considering whether an instruction would suffice can be reversed, just as a judge who denies one in the face of incurable prejudice can be. The record the defense builds at the moment the evidence comes in becomes the foundation for any later appellate challenge.
When the defense, not the judge, controls the timing
There is an important wrinkle when the inadmissible evidence is the product of government overreach. If prosecutorial misconduct provokes the defense into requesting a mistrial, double jeopardy principles can bar a retrial. That protects an accused against a prosecutor who deliberately injects prejudicial material to force a do-over after the case is going badly for the government. These situations are rare and fact-intensive, but they illustrate why courts scrutinize how the inadmissible evidence reached the panel, not just that it did.
Practical takeaways
A military accused can absolutely request a mistrial when the prosecution puts inadmissible evidence before the panel, and RCM 915 provides the vehicle. The realistic expectation, though, is that the judge will first consider a curative instruction and grant a mistrial only when the prejudice is so severe that no instruction can fix it. For that reason, defense counsel should object immediately, preserve the issue with specificity, explain why lesser remedies fall short, and make a considered judgment about whether a mistrial truly serves the accused. Because military justice involves rules and procedures that differ from civilian courts, a service member facing this situation should consult a qualified military defense attorney about the specific facts of the case.
Disclaimer
This article is provided strictly for general educational and informational purposes. It is intended to explain how the Uniform Code of Military Justice (UCMJ), the Rules for Courts-Martial, the Military Rules of Evidence, and related military administrative processes work as a matter of public legal education. It does not constitute legal advice, a legal opinion, or a recommendation about any particular case, and it is not a substitute for advice from a qualified military defense attorney who can evaluate the specific facts and command, service, and jurisdictional circumstances involved.
Reading this article, or contacting any website on which it appears, does not create an attorney-client relationship between the reader and any law firm, attorney, or author. Every court-martial, nonjudicial punishment action, administrative separation, and security-clearance matter turns on its own facts, the charged articles, the convening authority, the service branch, and the evidence, and outcomes vary widely from one case to another.
Military law also changes over time. The Military Justice Act of 2016 (effective January 1, 2019) and subsequent National Defense Authorization Acts renumbered and rewrote many punitive articles, revised the Article 32 preliminary hearing, and altered sentencing, clemency, and appellate procedures. Statutes, regulations, executive orders, the Manual for Courts-Martial, and decisions of the service Courts of Criminal Appeals and the Court of Appeals for the Armed Forces may have been amended, superseded, or reinterpreted after this article was written, and article numbers or procedures cited here may have changed.
For these reasons, no reader should act or decline to act based on this content without first consulting a licensed attorney experienced in military justice about their own situation. The author and publisher make no warranty, express or implied, as to the accuracy, completeness, timeliness, or current applicability of the information provided, and disclaim any liability for any action taken or not taken in reliance on it. If you are facing investigation, charges, or an adverse administrative action, time limits may apply, and you should seek qualified counsel promptly.