When two or more service members are charged together as co-conspirators, the government often prefers a single joint trial. A joint trial is efficient, presents the full picture of the alleged agreement to one panel, and avoids duplicating witnesses. For an accused, however, being tried alongside a co-conspirator can create real prejudice. The rules that govern when co-accused may be separated for individual trials are found in the Rules for Courts-Martial, and they place a meaningful burden on the accused who wants to be tried alone.
Joinder of Co-Accused as the Starting Point
Co-conspirators may be jointly charged because their alleged offense arises from the same agreement and overt acts. Once the convening authority refers charges against multiple accused to a single court-martial, the default is a joint trial. Severance is the exception, and the accused seeking it must move for it and justify it. This is the reverse of the instinct many people have. The system does not presume separate trials for co-accused; it presumes that those charged together will be tried together unless a specific rule and a specific showing require otherwise.
The Governing Rule: R.C.M. 906(b)(9)
A motion to sever co-accused is a motion for appropriate relief governed by Rule for Courts-Martial 906(b)(9). This is distinct from a motion to sever offenses, which falls under R.C.M. 906(b)(10) and is granted only to prevent manifest injustice. The severance-of-accused rule allows the military judge to order separate trials when keeping the accused joined would unfairly prejudice one of them. The decision is committed to the sound discretion of the military judge, which shapes both the trial litigation and the standard of review on appeal.
When Severance Becomes Necessary
Several recurring situations support severing co-conspirators. One is the antagonistic or mutually exclusive defense, where one accused’s defense is that the other is the truly culpable party. When defenses are so hostile that the panel cannot fairly evaluate one without effectively condemning the other, a joint trial can deprive an accused of a fair proceeding.
Another classic ground arises from out-of-court statements by a co-accused that implicate the moving accused. If a co-conspirator made a confession or admission naming the other, and that co-accused does not testify, the moving accused cannot cross-examine the person who made the statement. Admitting such a statement in a joint trial can collide with the accused’s confrontation rights. Severance, or redaction with a limiting instruction, is the tool used to address that problem.
A third ground is the spillover of evidence admissible against one accused but not the other. In a joint trial, the panel hears all the evidence at once, and there is a risk it will improperly attribute one accused’s conduct to the other.
The Standard the Accused Must Meet
The military judge has discretionary power over severance, and an abuse of that discretion will be found only where the accused shows that denial of severance caused actual prejudice that prevented a fair trial. Generalized claims that a joint trial is inconvenient or that the evidence against a co-accused is unflattering are not enough. The accused must connect the joinder to a concrete, fairness-defeating consequence.
When appellate courts review whether a denial of severance produced manifest injustice, they have applied a three-prong analysis: whether evidence of one matter would be admissible in proof of the other, whether the military judge gave a proper limiting instruction, and whether the findings reflect an impermissible crossover of evidence between the accused. If evidence would have been cross-admissible anyway, if the judge instructed the panel to consider evidence only against the accused to whom it applied, and if the verdict shows the panel kept the cases separate, then a joint trial is unlikely to be disturbed.
Alternatives a Military Judge May Use
Severance is not the only remedy. Because separate trials consume resources, a military judge will often consider less drastic measures first. Redacting a co-accused’s statement to remove references to the moving accused, giving carefully tailored limiting instructions, or controlling the order and manner of proof can address prejudice without splitting the trial. An accused arguing for severance should be prepared to explain why these lesser measures cannot cure the specific prejudice presented.
Why This Matters for the Defense
For a service member charged in a conspiracy, the severance decision can shape the entire case. A joint trial may expose the accused to a co-accused’s damaging statements, to antagonistic finger-pointing, and to the cumulative weight of evidence directed at the group. A successful severance motion isolates the government’s proof against the individual accused and forces the prosecution to prove that person’s participation in the agreement on its own merits.
Conclusion
Severance of co-conspirators in military court is governed by R.C.M. 906(b)(9) and rests in the military judge’s discretion. The default is a joint trial, and the accused bears the burden of showing actual prejudice that would deny a fair proceeding, whether through antagonistic defenses, an unconfrontable co-accused statement, or harmful evidentiary spillover. Because the standard is demanding and the remedies graduated, a service member facing a joint conspiracy trial should work with experienced military defense counsel to build a precise, prejudice-based record in support of any severance motion.
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.
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