You’re staring at an MBE question where the defendant gets arrested, the jury deadlocks, and then the prosecutor wants to retry him. Can they? The answer depends entirely on whether jeopardy attached in the first place—and whether one of the specific exceptions applies. Double jeopardy questions appear on nearly every MBE, and they’re testing whether you can spot the difference between a mistrial, an acquittal, and a dismissal. Let’s break down exactly when the Fifth Amendment protects a defendant from being tried twice.

What Double Jeopardy Actually Protects Against

The Fifth Amendment provides that no person shall “be subject for the same offense to be twice put in jeopardy of life or limb.” On the MBE, this translates to three distinct protections: (1) protection against a second prosecution for the same offense after acquittal, (2) protection against a second prosecution for the same offense after conviction, and (3) protection against multiple punishments for the same offense in a single proceeding.

Notice what’s missing from that list: protection against retrial after a mistrial. That’s the trap. Double jeopardy on the MBE doesn’t mean the government can never retry you—it means they can’t retry you after certain final outcomes. If the first trial ends without a definitive resolution on the merits, jeopardy often hasn’t terminated in a way that bars reprosecution.

The threshold question is always: When does jeopardy attach? In a jury trial, jeopardy attaches when the jury is sworn. In a bench trial, jeopardy attaches when the first witness is sworn. Until that moment, the government can dismiss and refile charges without triggering double jeopardy protections. Once jeopardy attaches, the analysis shifts to whether the termination of proceedings bars retrial.

Acquittals: The Absolute Bar to Retrial

An acquittal is the gold standard of double jeopardy protection. Once a defendant is acquitted—whether by a jury verdict, a bench trial finding, or a ruling by the judge that the evidence is legally insufficient—the government cannot retry the defendant for that offense. Period. It doesn’t matter if the judge made a legal error. It doesn’t matter if new evidence surfaces the next day proving guilt beyond any doubt. The acquittal stands, and double jeopardy bars any further prosecution.

Here’s where students get tripped up: a dismissal for insufficient evidence before the case goes to the jury is treated as an acquittal for double jeopardy purposes. If the judge grants a motion for judgment of acquittal at the close of the prosecution’s case, that’s functionally an acquittal. The defendant walks, and the government cannot appeal or retry.

Contrast that with a dismissal on procedural grounds—say, a speedy trial violation or a defective indictment. Those dismissals are not acquittals. They don’t resolve the factual question of guilt or innocence. The government can fix the procedural problem and refile charges, assuming the statute of limitations hasn’t run.

Hypothetical: Defendant is charged with robbery. At trial, after the prosecution rests, the judge grants the defendant’s motion for judgment of acquittal, finding that no reasonable jury could conclude the defendant used force. The prosecution appeals, arguing the judge misapplied the law. Can the appellate court reverse and order a new trial? No. The judgment of acquittal is treated as an acquittal on the merits, and double jeopardy bars any retrial, even if the trial judge was wrong.

Mistrials: When Retrial Is Allowed

A mistrial occurs when the trial is terminated before a verdict without resolving the defendant’s guilt. The classic example is a hung jury—the jury cannot reach a unanimous verdict, so the judge declares a mistrial. In that scenario, the government can retry the defendant because jeopardy never terminated in the defendant’s favor. The jury deadlock isn’t an acquittal; it’s simply a failure to reach a conclusion.

But not all mistrials allow retrial. The critical question is whether there was manifest necessity for the mistrial or whether the defendant consented to it. If the mistrial was declared over the defendant’s objection and without manifest necessity, double jeopardy bars retrial.

Manifest necessity exists when circumstances make it impossible or impractical to continue the trial. A hung jury qualifies. So does juror misconduct, a medical emergency involving a juror or the judge, or a witness becoming unavailable through no fault of the prosecution. If the judge declares a mistrial for one of these reasons, the government can retry the defendant.

If the defendant requests or consents to the mistrial, the government can also retry. The logic is straightforward: the defendant chose to abort the first trial, so they can’t invoke double jeopardy to prevent a second one. But if the prosecution goads the defendant into requesting a mistrial through misconduct, some courts will find that double jeopardy bars retrial. The test is whether the prosecutorial misconduct was intended to provoke the mistrial.

Hypothetical: During trial, a witness blurts out that the defendant “refused to take a polygraph.” Defense counsel immediately moves for a mistrial, which the judge grants. Can the government retry the defendant? Yes. The defendant requested the mistrial, so double jeopardy does not bar retrial, even though the mistrial resulted from the prosecution’s failure to properly instruct the witness.

Convictions Overturned on Appeal

If a defendant is convicted and successfully appeals, the general rule is that the government can retry the defendant. The defendant waived double jeopardy protections by seeking appellate review. There’s one major exception: if the appellate court reverses because the evidence was insufficient to support the conviction, double jeopardy bars retrial. That’s treated the same as an acquittal.

But if the reversal is based on a trial error—improper jury instructions, evidentiary rulings, prosecutorial misconduct that wasn’t intended to provoke a mistrial—the government gets another shot. The conviction is wiped out, but jeopardy never terminated in the defendant’s favor, so retrial is permitted.

Hypothetical: Defendant is convicted of burglary. On appeal, the appellate court finds that the trial judge gave an incorrect instruction on the “intent to commit a felony” element, and reverses the conviction. Can the government retry the defendant? Yes. The reversal was based on a trial error, not on insufficient evidence, so double jeopardy does not bar retrial.

Now change the facts: the appellate court reverses because no reasonable jury could have found that the defendant entered the building with intent to commit a felony inside. Can the government retry? No. The reversal was based on insufficient evidence, which is treated as an acquittal for double jeopardy purposes.

The Same Offense Problem

Even when double jeopardy doesn’t bar retrial for the same charge, it may bar prosecution for a different charge arising from the same conduct. The test is the Blockburger test: two offenses are the same for double jeopardy purposes unless each requires proof of an element the other does not.

If the defendant is acquitted of robbery, can the government then charge him with larceny based on the same taking? No. Robbery is larceny plus force or intimidation. Every element of larceny is included in robbery, so they’re the same offense under Blockburger. The acquittal on robbery bars prosecution for larceny.

But if the defendant is acquitted of felony murder based on an underlying robbery, can the government charge him with the robbery itself? Yes. Robbery and felony murder each require proof of an element the other does not. Felony murder requires proof of a death; robbery does not. Robbery requires proof of intent to permanently deprive; felony murder does not (the intent to commit the felony supplies the malice). They’re separate offenses, so an acquittal on one doesn’t bar prosecution for the other.

Lesser included offenses create a special rule. If the defendant is convicted of a greater offense, they cannot later be prosecuted for a lesser included offense. And if they’re acquitted of a greater offense, they cannot be prosecuted for a lesser included offense that was presented to the jury. The acquittal of the greater implicitly acquits on the lesser.

Hypothetical: Defendant is charged with first degree murder. The jury is instructed on first degree murder, second degree murder, and voluntary manslaughter. The jury acquits on all counts. Can the government then charge the defendant with involuntary manslaughter based on the same killing? Courts are split, but the majority rule is no—the acquittal on voluntary manslaughter (which requires a higher level of culpability) implicitly acquits on involuntary manslaughter, even though the jury wasn’t instructed on it.

Separate Sovereigns Exception

Here’s the exception that feels unfair but is firmly established: the separate sovereigns doctrine. Double jeopardy does not bar successive prosecutions by different sovereigns for the same conduct. The federal government and a state government are separate sovereigns. Two different states are separate sovereigns. A state and a Native American tribe are separate sovereigns.

This means a defendant can be prosecuted in federal court for a federal offense and then prosecuted in state court for a state offense arising from the same act, or vice versa. The Fifth Amendment’s double jeopardy clause applies only to successive prosecutions by the same sovereign.

On the MBE, watch for fact patterns where the defendant is acquitted in state court and then charged in federal court. That’s permissible under the separate sovereigns doctrine, even though it feels like double jeopardy. The two prosecutions are by different governments exercising independent sovereign authority.

One important limitation: a state and a municipality within that state are not separate sovereigns. A city is a political subdivision of the state, so a conviction in municipal court bars a subsequent state prosecution for the same offense.

What You Need to Memorize for the MBE

When you see a double jeopardy question on the bar exam, work through this checklist:

  1. Did jeopardy attach? (Jury sworn in jury trial; first witness sworn in bench trial)
  2. How did the first proceeding terminate? (Acquittal, conviction, mistrial, dismissal)
  3. If acquittal: Retrial is barred, no exceptions.
  4. If conviction: Retrial is allowed if defendant appeals, unless reversal is based on insufficient evidence.
  5. If mistrial: Retrial is allowed if there was manifest necessity or defendant consented.
  6. If dismissal: Was it on the merits (treated as acquittal) or procedural (retrial allowed)?
  7. Same offense? Apply Blockburger: does each offense require proof of an element the other does not?
  8. Separate sovereigns? Federal and state prosecutions don’t violate double jeopardy.

The most commonly tested scenarios are hung jury mistrials (retrial allowed), judgments of acquittal based on insufficient evidence (retrial barred), and appellate reversals for trial error (retrial allowed) versus insufficient evidence (retrial barred). If you can distinguish those three, you’ll handle most double jeopardy questions correctly.

The rules interact with other criminal procedure doctrines you’re memorizing—speedy trial, jury selection, prosecutorial misconduct. That’s why double jeopardy often appears in the context of a larger fact pattern testing multiple constitutional protections. If you want all the criminal procedure rules organized for active recall, FlashTables Criminal Law & Procedure breaks down jeopardy attachment, mistrial standards, and the Blockburger test into a structured format that makes the distinctions clear. When you’re juggling 104 rules across criminal law and procedure, having them in one place saves you from flipping through outlines trying to remember whether manifest necessity applies to defendant-requested mistrials.

The bottom line: double jeopardy doesn’t mean the government only gets one shot. It means they can’t retry you after an acquittal, and they need a legally sufficient reason to retry you after a mistrial. Know when jeopardy attaches, know what counts as an acquittal, and know the manifest necessity standard. Those three concepts will carry you through every double jeopardy question the MBE throws at you.