A motion to sever is a pretrial request asking a federal judge to split joined criminal charges, or two or more codefendants, into separate trials. The authority comes from Federal Rule of Criminal Procedure 14, which lets a court order separate trials of counts, sever defendants, or grant any other relief that justice requires whenever joinder appears to prejudice a defendant.1Legal Information Institute. Federal Rules of Criminal Procedure Rule 14 – Relief from Prejudicial Joinder Prosecutors routinely bundle related offenses and codefendants into one indictment under Rule 8 for efficiency, but that bundling can poison a jury’s ability to judge each charge or each person fairly.2Legal Information Institute. Federal Rules of Criminal Procedure Rule 8 – Joinder of Offenses or Defendants The word “appears” in Rule 14 matters: the defendant does not have to prove prejudice already occurred, only that a meaningful risk exists.
Winning the motion can reshape the entire trajectory of a case. It can also backfire. Both sides of that trade deserve a close look before anyone files.
When a Court Will Sever Charges
The classic reason to sever counts is evidence spillover. Suppose someone faces a drug possession count and a completely unrelated fraud count in the same indictment. In separate trials, the fraud evidence would never reach the drug jury and vice versa. Tried together, a juror hearing about drug activity might assume the defendant is generally dishonest and convict on the fraud charge based on character rather than proof.
The standard is not whether the defendant would prefer separate trials. Courts ask whether a jury can realistically follow instructions to evaluate each count independently. Judges often conclude that a careful limiting instruction solves the problem, especially when the charges overlap factually and the same witnesses would testify in both trials anyway. Severance of charges tends to succeed only when the evidence on one count is inflammatory or emotionally charged enough that no instruction can realistically un-ring the bell.
When a Court Will Sever Codefendants
Separating defendants raises higher constitutional stakes. Three fact patterns come up most often.
A Codefendant’s Confession Names You
In Bruton v. United States, the Supreme Court held that admitting a non-testifying codefendant’s confession in a joint trial violates the other defendant’s Sixth Amendment right to cross-examination, even when the judge instructs the jury to ignore the confession as to the non-confessing defendant.3Justia. Bruton v. United States, 391 U.S. 123 (1968) The Court recognized a substantial risk that jurors would find it impossible to follow such an instruction. If one defendant gave a statement to police that names and implicates a codefendant, and the person who gave the statement will not take the stand, the accused codefendant has no way to challenge that evidence through cross-examination.4Legal Information Institute. Confrontation Clause Cases During the 1960s Through 1990s
Courts sometimes try to salvage the joint trial by redacting the confession to remove every reference to the other defendant. When redaction works cleanly, severance may not be needed. When the redaction is obvious or the remaining context still points to the codefendant, the constitutional problem persists and the trials must be separated.
You and Your Codefendant Are Blaming Each Other
When codefendants point fingers at each other, each one essentially becomes a second prosecutor against the other. The Supreme Court addressed this in Zafiro v. United States, holding that severance should be granted “only if there is a serious risk that a joint trial would compromise a specific trial right of a properly joined defendant or prevent the jury from making a reliable judgment about guilt or innocence.”5Legal Information Institute. Zafiro v. United States, 506 U.S. 534 (1993) Antagonistic defenses are not prejudicial as a matter of law, and the Court noted that less drastic alternatives like limiting instructions will often be enough. Many severance motions on this ground fail because the defense cannot show that the finger-pointing is so pervasive that no instruction can protect the jury’s ability to evaluate each defendant separately.
The Evidence Against You Is Dwarfed by the Evidence Against a Codefendant
A defendant with minimal involvement tried alongside an alleged ringleader risks guilt by association. The jury hears weeks of testimony about the leader’s violent acts, complex schemes, and recorded conversations, then must evaluate the peripheral defendant’s case with fresh eyes. Courts recognize this as spillover prejudice, though they remain reluctant to sever on this ground alone unless the disparity is extreme.
Filing Deadlines and What Goes in the Motion
Under Federal Rule of Criminal Procedure 12(b)(3)(D), a motion to sever charges or defendants must be raised as a pretrial motion. The court typically sets a specific deadline at or shortly after arraignment. If no deadline is set, the default cutoff is the start of trial. Filing late does not automatically kill the motion, but the defense must show good cause for missing the deadline, which is a harder sell than filing on time.6Legal Information Institute. Federal Rules of Criminal Procedure Rule 12 – Pleadings and Pretrial Motions
The motion itself is a written filing that identifies the indictment, the specific counts or defendants the defense wants separated, and the legal basis for the request. It is typically accompanied by a memorandum of law laying out the factual and legal arguments for prejudice. Supporting exhibits might include redacted transcripts of police interrogations, discovery materials showing conflicting codefendant statements, or a proffer of how the evidence at a joint trial would unfold. Many federal districts also require defense counsel to confer with the prosecution in good faith before filing and to certify that effort in the motion papers. Local rules on formatting, page limits, and electronic filing vary significantly from district to district, so check them before drafting.
What Happens After the Motion Is Filed
Once the motion is filed and served, the government gets an opportunity to file an opposition brief. The timeframe depends on the court’s scheduling order and local rules; there is no single federal deadline that applies everywhere. The defense may then file a reply.
The judge usually schedules a hearing after briefing is complete. Both sides argue, and the judge may press defense counsel on exactly how the joint trial would cause prejudice beyond the ordinary inconvenience of facing multiple charges. Judges have wide discretion. A ruling might come from the bench immediately or arrive as a written order days or weeks later.
If the motion is granted, the court schedules separate trial dates with entirely new jury selections for each proceeding. The court may also issue orders about how evidence will be handled across the now-separate cases. If the motion is denied, the defendant should renew it at the close of evidence. Failing to renew can weaken the argument on appeal by suggesting the defendant abandoned the issue, and some circuits treat an unrenewed motion as forfeited.
The Hidden Costs of Winning Severance
Defense attorneys sometimes treat severance as an unqualified win. It is not always one.
Separate Trials Can Raise Your Sentence
When multiple charges are resolved together in a single trial or plea, many sentencing systems treat the resulting convictions as a single event for purposes of calculating a defendant’s criminal history. Sever the charges into separate proceedings, and each conviction becomes its own sentencing event. A conviction in the first trial can count as a prior record point at the second sentencing, potentially pushing the defendant into a higher sentencing range. What would have been a single prior conviction becomes a stepping stone to recidivist status.
You May Waive Double Jeopardy Protection
In Currier v. Virginia, the Supreme Court held that when a defendant consents to severance of charges, the defendant effectively waives the Double Jeopardy Clause’s protection against relitigation of issues resolved in the first trial. Winning an acquittal in the first trial does not necessarily block the prosecution from trying the defendant on related charges in the second trial, even if the second case depends on facts the first jury rejected. The Court reasoned that a defendant who chooses separate trials “wins a potential benefit and experiences none of the prosecutorial oppression the Double Jeopardy Clause exists to prevent.”7Justia. Currier v. Virginia, 585 U.S. (2018) A favorable verdict at the first trial may not carry the preclusive force the client expects.
The Prosecution Gets a Second Rehearsal
Separate trials mean the prosecution gets to run its case once, see what works and what falls flat, and adjust for the next trial. Witnesses who were shaky the first time get better with practice. Defense strategies that worked once become predictable. A codefendant convicted in the first trial may decide to cooperate and testify against the remaining defendant in exchange for sentencing consideration. The defense does get one offsetting advantage: if a codefendant is tried first, defense counsel gains full discovery of the prosecution’s courtroom presentation before their own trial begins.
Appealing a Denied Motion
Appellate courts review severance denials under an abuse-of-discretion standard, which is among the most deferential standards in federal law. It is not enough to argue that separate trials would have improved the chances of acquittal. The appellant must demonstrate that the denial caused clear and substantial prejudice resulting in a fundamentally unfair trial.8Justia Law. United States v. Lopez-Martinez, No. 17-1924 (1st Cir. 2021)
Federal courts recognize that some degree of garden-variety prejudice exists in any joint trial. A defendant who simply shows that the joint trial was imperfect or uncomfortable will not meet the threshold. The prejudice must be specific: a concrete trial right was compromised, or the jury was prevented from making a reliable determination of guilt or innocence, consistent with Zafiro.5Legal Information Institute. Zafiro v. United States, 506 U.S. 534 (1993) Successful appeals are uncommon. The strongest cases involve clear Bruton violations or situations where the trial court ignored overwhelming evidence of spillover prejudice between defendants with vastly different levels of culpability.