A joint trial is a single court proceeding that combines either multiple criminal charges against one defendant or multiple defendants charged with related conduct. In federal court, Rules 8 and 13 of the Federal Rules of Criminal Procedure decide when charges and defendants can be grouped, and Rule 14 decides when a defendant can pry them apart. Judges tend to favor grouping because it conserves court time and spares witnesses from testifying twice, but the Constitution and the rules set real limits on how far that preference can go.
When Charges Against One Defendant Can Be Joined
Federal Rule of Criminal Procedure 8(a) lets prosecutors charge a single defendant with two or more offenses in the same indictment when the offenses share a meaningful connection. They can be grouped if they are similar in character, grow out of the same act, or form parts of a broader scheme.1Justia Law. Fed. R. Crim. P. 8 – Joinder of Offenses or Defendants A bank robbery defendant might face armed robbery, firearms possession, and conspiracy counts in one proceeding because each charge traces back to the same plan.
The “similar character” prong is the broadest. It does not require the offenses to arise from the same event at all. Two unrelated fraud schemes against the same defendant can be joined simply because both involve fraud. That saves the court from empaneling a second jury to hear the same type of evidence, and it is also precisely why defendants ask for severance: jurors who hear about two frauds may be more willing to believe a defendant committed either one.
When Multiple Defendants Can Be Tried Together
Rule 8(b) controls joint trials of co-defendants. The government may charge two or more people in the same indictment when they allegedly participated in the same act or in the same series of connected acts.2Legal Information Institute. Federal Rules of Criminal Procedure Rule 8 – Joinder of Offenses or Defendants A drug conspiracy is the textbook example: the supplier, the courier, and the street-level dealer can be tried together because each role is part of a single distribution chain.
Even when co-defendants are charged in separate indictments, Rule 13 lets the court order them tried together, as long as everyone and everything could have been joined in one indictment from the start. This matters because prosecutors sometimes file charges at different stages of an investigation. Rule 13 lets the court reunify the cases without starting over.
Grounds for Severance
Rule 14(a) provides that if joinder appears to prejudice a defendant or the government, the court may order separate trials or grant whatever other relief justice requires.3Legal Information Institute. Federal Rules of Criminal Procedure Rule 14 – Relief from Prejudicial Joinder Severance is discretionary. The Supreme Court in Zafiro v. United States set the bar high: a court should grant severance only when there is a serious risk that the joint trial would compromise a specific trial right or prevent the jury from reliably judging guilt or innocence.4Legal Information Institute. Zafiro v. United States
Mutually Antagonistic Defenses
One common severance argument involves defendants who point the finger at each other. If one person’s entire defense is “the other did it,” believing one defendant seems to require convicting the other. Defendants in that position often argue severance is required. Zafiro rejected that bright-line rule, holding that conflicting defenses are not automatically prejudicial.4Legal Information Institute. Zafiro v. United States A defendant still has to show a serious risk of an unfair verdict. In many cases, the court will deny severance and instead instruct the jury to evaluate each defendant’s evidence on its own.
Spillover Prejudice
A more concrete basis for severance arises when evidence admissible against one defendant would be devastating to a co-defendant but inadmissible in a separate trial. A co-defendant with a long criminal record and graphic evidence of violence can poison the jury’s view of everyone at the defense table. Courts weigh whether limiting instructions can cure the problem or whether the prejudice runs too deep.
Misjoinder Versus Prejudicial Joinder
These two concepts sound alike but do different work. Misjoinder means the charges or defendants were improperly combined under Rule 8 in the first place, so the cases never should have been grouped. Prejudicial joinder under Rule 14 arises when the joinder was technically proper but the joint trial still creates unfair prejudice. The Advisory Committee notes to Rule 14 confirm that severance for prejudicial joinder is left to the trial court’s discretion, though appellate courts have sometimes found that denying it amounted to reversible error.3Legal Information Institute. Federal Rules of Criminal Procedure Rule 14 – Relief from Prejudicial Joinder
The Bruton Problem With Co-Defendant Confessions
Joint trials raise a specific constitutional problem when one defendant has confessed and the other has not. Under Bruton v. United States (1968), the Sixth Amendment’s Confrontation Clause bars prosecutors from introducing a non-testifying co-defendant’s confession at a joint jury trial if the confession implicates the other defendant. The non-confessing defendant has no way to cross-examine someone who stays off the witness stand, and the confession carries what the Court called “substantial, perhaps even critical, weight” in a form the defense cannot challenge.5Legal Information Institute. Confrontation Clause Cases During the 1960s Through 1990s
Later cases carved out a narrow path. A confession can be redacted to remove not just the co-defendant’s name but any reference to their existence, then admitted with a limiting instruction. Simply replacing the name with a blank or the word “deleted” is not enough; the Supreme Court in Gray v. Maryland (1998) held that obvious redactions still violate the Confrontation Clause.5Legal Information Institute. Confrontation Clause Cases During the 1960s Through 1990s
Before ruling on a severance motion that involves this issue, Rule 14(b) lets the court order the government to submit the co-defendant’s statement for private judicial review, so the judge can decide whether redaction will work or whether separate trials are the only fair option.3Legal Information Institute. Federal Rules of Criminal Procedure Rule 14 – Relief from Prejudicial Joinder
Limiting Instructions Instead of Severance
Judges reach for limiting instructions far more often than they grant severance. A limiting instruction tells the jury to consider certain evidence only against the defendant it was admitted against, or only for a particular purpose. Zafiro endorsed this approach, noting that less drastic measures will often suffice even when some risk of prejudice exists.4Legal Information Institute. Zafiro v. United States
The honest reality is that limiting instructions ask jurors to perform a mental exercise that may be impossible. Once a jury has heard a co-defendant’s detailed confession, telling them to disregard it as to the other defendant strains credulity. The Advisory Committee notes to Rule 14 acknowledge this directly, stating that limiting instructions “may not in fact erase the prejudice” caused by a co-defendant’s confession.3Legal Information Institute. Federal Rules of Criminal Procedure Rule 14 – Relief from Prejudicial Joinder The tension between the legal presumption that jurors follow instructions and the practical doubt about whether they can is where most severance disputes play out.
How to Ask for Severance
A motion to sever has to show that the joint trial creates a genuine risk of an unfair outcome. The motion should pinpoint the specific prejudice, whether that is conflicting defenses, inflammatory evidence spilling over from a co-defendant, or a confession that implicates someone who cannot cross-examine the person who made it.
In federal criminal cases, a severance motion is a pretrial motion that must be raised before trial. Rule 12(c) tells the court to set a pretrial motion deadline at or shortly after arraignment. If the court never sets one, the default cutoff is the start of trial. Missing the deadline does not automatically kill the motion, but the court will only consider a late filing if the defendant shows good cause.6Legal Information Institute. Federal Rules of Criminal Procedure Rule 12 – Pleadings and Pretrial Motions
Civil Consolidation Is a Separate Track
Civil litigation has its own grouping mechanism and it is not what Rule 14 severance is about. Under Federal Rule of Civil Procedure 42(a), a judge can consolidate separate lawsuits pending before the same court when they share a common question of law or fact.7Legal Information Institute. Federal Rules of Civil Procedure Rule 42 – Consolidation; Separate Trials When related civil actions are scattered across multiple federal districts, 28 U.S.C. § 1407 allows a special judicial panel to transfer them to a single district for coordinated pretrial proceedings.8Office of the Law Revision Counsel. 28 USC 1407 – Multidistrict Litigation These civil tools are about efficiency, not Confrontation Clause rights, and the standards are not interchangeable with the criminal rules above.
Appealing a Severance Ruling
Appellate courts review a trial court’s decision to grant or deny severance for abuse of discretion. That is a deferential standard. A defendant has to show not just that the trial court made a questionable call, but that the decision fell outside the range of reasonable options. In Zafiro, the Supreme Court affirmed a severance denial because the defendants relied on a bright-line rule instead of showing actual prejudice from their joint trial.4Legal Information Institute. Zafiro v. United States
Timing is the other hurdle. A defendant usually cannot appeal a severance denial before the trial ends. Joinder and severance orders are not among the decisions eligible for immediate interlocutory appeal under 28 U.S.C. § 1292(a).9Office of the Law Revision Counsel. 28 USC 1292 – Interlocutory Decisions A party can try to get certification under § 1292(b) by convincing the trial judge that the order involves a controlling question of law with substantial grounds for disagreement, but courts rarely grant that for severance rulings. In practice, a defendant who loses a severance motion sits through the joint trial and raises the issue on appeal after a conviction.