The difference between a mistrial and a hung jury is cause versus effect. A hung jury is what happens inside the jury room when jurors finish deliberating and remain too divided to deliver a verdict. A mistrial is what the judge does about it: a formal ruling that ends the trial without a final outcome. Every hung jury leads to a mistrial, but plenty of mistrials have nothing to do with jury disagreement at all.
What a Hung Jury Is
A hung jury exists only after deliberations have started. In criminal cases involving serious offenses, a conviction or acquittal must be unanimous.1Constitution Annotated. Constitution Annotated – Amdt6.4.4.3 Unanimity of the Jury When jurors report they cannot get there, the judge almost never accepts the deadlock on the first try. The usual response is to send them back for more deliberation, sometimes with a supplemental instruction called an Allen charge, named for the 1896 Supreme Court case that first approved it. The instruction asks jurors to listen to each other and reconsider positions that may be unreasonable. Critics argue it pressures minority-opinion jurors into giving in. Federal courts still use Allen charges with caution, and several states have banned them.2United States Court of Appeals for the Ninth Circuit. Manual of Model Criminal Jury Instructions – 7.7 Deadlocked Jury
If the jury still cannot agree after further deliberation, the judge declares the jury hung and ends the trial.
What a Mistrial Is
A mistrial is a judge’s ruling that a trial cannot continue fairly and must be terminated without a verdict. Everything that happened during the trial is essentially wiped out. Unlike a hung jury, which can only occur once deliberations are underway, a mistrial can be declared at any point during the proceedings.
Common reasons for a mistrial unrelated to jury deadlock include:
- Attorney misconduct, such as mentioning evidence the judge already ruled inadmissible or making inflammatory statements designed to prejudice the jury.
- Juror misconduct, such as researching the case online, discussing it with outsiders, or concealing a bias during jury selection.
- Serious procedural errors in how evidence was admitted or how the jury was instructed that are too damaging to fix with a corrective instruction.
- Loss of a key participant, such as the serious illness or death of a juror (when no alternates remain), an attorney, or the judge.
The thread running through all of these is that something has gone wrong enough to make a fair verdict unreachable.
How the Two Connect
Put simply: “hung jury” describes what happened with the jurors, and “mistrial” describes what the judge did about it. A hung jury is one cause of a mistrial. Attorney misconduct, procedural errors, and the other problems above produce the same legal result without any jury disagreement.
Partial Verdicts in Multi-Count Cases
When a defendant faces multiple charges, a jury might agree on some counts but deadlock on others. The jury returns its verdict on the counts where it reached agreement, and the judge declares a mistrial only on the remaining counts. The convictions or acquittals on the decided counts stand. The prosecution can then choose whether to retry the defendant on the unresolved charges alone.3Legal Information Institute. Federal Rules of Criminal Procedure Rule 31 – Jury Verdict
What Happens After Either One
A mistrial does not end the case permanently. It resets it. The prosecution in a criminal case generally has three options: retry the case with a new jury, negotiate a plea deal, or drop the charges. Which path gets chosen usually depends on how the first trial went. If the evidence was strong and the jury split heavily toward conviction, a retrial is likely. If the case looked weak or the jury leaned toward acquittal, prosecutors may offer a favorable plea deal or walk away.
For the defendant, a mistrial means continued uncertainty. Someone out on bail before the first trial typically remains on bail under the same or modified conditions. A defendant held in custody generally stays in custody pending retrial. The court has discretion to adjust bail based on how circumstances may have changed. The defendant returns to roughly the same position they were in before trial started, now facing the prospect of going through the whole process again.
The Retrial Clock
In federal cases, the prosecution cannot take its time. The Speedy Trial Act requires that a new trial begin within 70 days after the mistrial is declared.4Office of the Law Revision Counsel. 18 USC 3161 – Time Limits for Beginning of Trial Certain delays, such as time spent on pretrial motions, do not count against that clock. State courts have their own speedy trial rules with varying timelines, but the underlying principle is the same: the government cannot leave a defendant in legal limbo indefinitely.
When Double Jeopardy Blocks a Retrial
The Fifth Amendment’s Double Jeopardy Clause prevents someone from being tried twice for the same crime after a final verdict. A mistrial does not produce a final verdict. That distinction is what allows retrials. The Supreme Court has long held that when a mistrial results from “manifest necessity,” such as a jury that cannot agree, retrying the defendant does not violate double jeopardy.5Constitution Annotated. Constitution Annotated – Amdt5.3.4 Re-Prosecution After Mistrial
That rule applies cleanly to most mistrials caused by hung juries, procedural errors, or unavoidable disruptions. There are situations, though, where double jeopardy does block a second trial.
When the Defendant Asked for the Mistrial
If the defense moves for a mistrial because of the prosecution’s bad behavior, the defendant can usually be retried. The reasoning is that the defendant chose to end the trial rather than risk a tainted verdict. The Supreme Court carved out one exception in Oregon v. Kennedy: if the prosecutor’s misconduct was deliberately intended to provoke the defendant into requesting a mistrial, double jeopardy bars a retrial.5Constitution Annotated. Constitution Annotated – Amdt5.3.4 Re-Prosecution After Mistrial A prosecutor should not get a do-over after sabotaging a trial that was going badly.
This is a hard standard. The defendant must show that the prosecutor specifically intended to goad them into requesting a mistrial, not merely that the prosecutor acted recklessly or improperly.
When the Judge Declared the Mistrial Over the Defendant’s Objection
The analysis changes when the judge ends the trial without the defendant’s consent. The prosecution must then show the mistrial was genuinely necessary. A deadlocked jury almost always clears this bar. Harder cases arise when the judge halts the trial over a procedural error or prosecutorial overreach that arguably could have been fixed with a lesser remedy. If a reviewing court later finds the mistrial was not truly necessary, double jeopardy may prevent a second trial.5Constitution Annotated. Constitution Annotated – Amdt5.3.4 Re-Prosecution After Mistrial
What Carries Over to a Retrial
A retrial starts fresh with a new jury, but testimony from the first trial does not vanish. If a witness is no longer available, their prior testimony may be admitted under a hearsay exception. More commonly, if a defendant testifies at the retrial and says something inconsistent with what they said the first time, the prosecution can use the earlier testimony to challenge their credibility on cross-examination. Some defendants assume a mistrial erases everything they said on the stand. It does not.