California Bar Double Jeopardy
Last updated: May 2, 2026
Double Jeopardy questions are one of the highest-leverage areas to study for the California Bar. This guide breaks down the rule, the elements you need to recognize, the named traps that catch most students, and a memory aid that scales to test day. Read it once, then practice the same sub-topic adaptively in the app.
The rule
The Fifth Amendment's Double Jeopardy Clause, applied to the states through the Fourteenth Amendment (Benton v. Maryland), prohibits (1) a second prosecution for the same offense after acquittal, (2) a second prosecution for the same offense after conviction, and (3) multiple punishments for the same offense in a single proceeding. Jeopardy attaches in a jury trial when the jury is empaneled and sworn, in a bench trial when the first witness is sworn, and in a guilty-plea proceeding when the court accepts the plea. Two offenses are the 'same offense' under the Blockburger 'same elements' test (Blockburger v. United States): they are the same unless each statute requires proof of a fact the other does not. The dual-sovereignty doctrine permits successive prosecutions by separate sovereigns (federal/state, state/state), but the State of California by statute (Cal. Penal Code § 656) bars a California prosecution where the defendant has already been acquitted or convicted in another jurisdiction for an act based on the same conduct that was an element of the prior offense — a meaningful California deviation from the federal rule.
Elements breakdown
Attachment of Jeopardy
Jeopardy must attach before any double-jeopardy bar can operate; without attachment there is no constitutional protection.
- Jury trial: jury empaneled and sworn
- Bench trial: first witness sworn in
- Guilty plea: court accepts the plea
- Juvenile adjudication: hearing on merits begins
Common examples:
- Pretrial dismissal for insufficient evidence (no attachment, retrial allowed)
- Mistrial declared before jury sworn (no attachment)
Termination Triggering the Bar (Acquittal)
A factfinder's resolution of any factual element in defendant's favor terminates jeopardy and bars retrial, regardless of label.
- Factfinder ruling resolves a factual element
- Ruling is in defendant's favor
- Resolution goes to substance, not procedure
Common examples:
- Judgment of acquittal under FRCP 29
- Directed verdict of not guilty
- Implied acquittal on greater offense when convicted of lesser
Same-Offense Test (Blockburger)
Two statutory offenses are the 'same offense' for double-jeopardy purposes unless each requires proof of an element the other does not.
- Compare statutory elements, not facts proved
- Each offense must require a unique element
- If yes to both, offenses are different
- If no, they are the same offense
Common examples:
- Greater and lesser-included offenses are the 'same offense'
- Felony murder and underlying felony are the same offense (Harris v. Oklahoma)
Mistrial — Defendant's Motion or Manifest Necessity
A mistrial bars retrial only when granted over defendant's objection without manifest necessity, or when prosecutor goaded the defendant into moving for one.
- If defendant moves for mistrial: retrial generally permitted
- Exception: prosecutorial goading designed to provoke motion
- If granted over defendant's objection: requires manifest necessity
- Examples of necessity: hung jury, juror misconduct, prejudicial publicity
Common examples:
- Hung jury (manifest necessity, retrial allowed)
- Prosecutor's intentional misconduct provoking mistrial motion (bar applies)
Multiple Punishments in Single Proceeding
The legislature may authorize cumulative punishments for the same conduct in one proceeding; double-jeopardy review is limited to legislative intent.
- Single proceeding (not successive prosecutions)
- Court determines legislative intent
- If legislature authorized cumulative sentences, no bar
- Blockburger applied as default canon of construction
Common examples:
- Missouri v. Hunter (legislature may stack same-offense sentences in one trial)
- Sentence enhancements based on prior conduct
Dual Sovereignty and California's Statutory Override
Separate sovereigns may each prosecute, but California has enacted a statutory bar against successive prosecutions for the same act.
- Federal rule: separate sovereigns may prosecute (Heath v. Alabama; Gamble v. United States)
- California statute: Cal. Penal Code § 656
- Bar applies when prior acquittal or conviction in another jurisdiction
- Prior offense's element must be based on the same act
Common examples:
- Federal acquittal followed by California prosecution: § 656 bars
- State A acquittal followed by State B prosecution: § 656 bars in California
- Civil forfeiture not a 'prosecution' (Hudson v. United States)
Collateral Estoppel (Issue Preclusion)
Embedded within the Double Jeopardy Clause (Ashe v. Swenson), an issue of ultimate fact decided in defendant's favor cannot be relitigated in a later prosecution between the same parties.
- Issue of ultimate fact
- Necessarily decided in prior proceeding
- In defendant's favor
- Same parties (defendant and same sovereign)
Common examples:
- Ashe v. Swenson — acquittal of robbery of one poker player barred prosecution for robbery of another from same incident
Common patterns and traps
The Pre-Attachment Mirage
The fact pattern dangles a pre-trial dismissal, an arrest without charges, or a grand-jury no-bill and tempts you to call it a double-jeopardy bar. Jeopardy never attached, so the Clause does nothing. The trap works because students conflate 'in trouble with the law' with 'in jeopardy' — they are not the same.
An answer choice reading 'Yes, because the prior dismissal bars retrial' or 'No, because jeopardy attached when the indictment was filed.'
The Same-Conduct Decoy
A distractor restates Blockburger as a 'same act' or 'same transaction' test. This is the rule rejected by the Court (United States v. Dixon overruled Grady v. Corbin's same-conduct test). Watch for any choice that compares what the defendant did rather than what the statutes require to be proved.
A choice saying 'the offenses are the same because both arose from the same robbery' rather than 'because each statute requires proof of an element the other does not.'
The Manifest-Necessity Misread
When a mistrial is declared, students reflexively conclude either 'always retrial' or 'never retrial.' Both are wrong. The pivot is who moved for the mistrial and, if over defendant's objection, whether manifest necessity supported it. Hung juries are the canonical manifest-necessity case.
A choice asserting 'No retrial because a mistrial terminates jeopardy' or 'Retrial permitted because mistrials never bar reprosecution.'
The California § 656 Switch
On California essays and California-flavored MBE-style items, the dual-sovereignty answer that wins federally loses in California. Cal. Penal Code § 656 bars a California prosecution where the defendant was previously acquitted or convicted in another jurisdiction for an act that was an element of the prior offense. Distractors will faithfully recite Heath/Gamble and ignore § 656.
A choice reading 'Yes, the California prosecution may proceed because separate sovereigns may each prosecute the same conduct.'
The Civil-Sanction Red Herring
A vignette mentions a prior civil forfeiture, license revocation, or administrative penalty and asks whether a criminal prosecution is now barred. Under Hudson v. United States, civil sanctions are not 'punishment' for double-jeopardy purposes unless so punitive in purpose or effect as to transform the proceeding. Most administrative consequences do not trigger the bar.
A choice answering 'No, because the prior civil forfeiture already punished the defendant for the same offense.'
How it works
Picture this: Reyes is charged with armed robbery of a Sacramento liquor store. The jury is empaneled and sworn — jeopardy attaches at that instant. Mid-trial, the prosecutor learns a key witness lied; she moves for a mistrial over Reyes's objection. Unless the judge finds 'manifest necessity,' Reyes cannot be retried. Suppose instead the jury acquits Reyes of armed robbery but convicts him of simple robbery (a lesser-included offense); the prosecution may not later retry the armed-robbery charge because under Blockburger the greater and lesser-included offenses are the 'same offense' and the acquittal is final. Now layer on California's twist: if the U.S. Attorney later indicts Reyes federally for Hobbs Act robbery based on the same heist, federal dual-sovereignty doctrine permits it — but if the order were reversed (federal first, then California), Cal. Penal Code § 656 would bar the California charge.
Worked examples
Will Patel's double-jeopardy motion succeed?
- A Yes, because jeopardy attached when the jury was sworn and any second trial after a mistrial violates the Double Jeopardy Clause.
- B Yes, because the prosecutor's discovery violation amounted to manifest necessity in defendant's favor.
- C No, because Patel moved for the mistrial and the prosecutor's conduct was not intentional goading designed to provoke the motion. ✓ Correct
- D No, because jeopardy does not attach until the first witness is sworn, and the late disclosure occurred before that point.
Why C is correct: When a defendant moves for a mistrial, retrial is generally permitted because the defendant has chosen to terminate the trial. The Oregon v. Kennedy exception bars retrial only when the prosecutor's misconduct was specifically intended to goad the defendant into moving for a mistrial. The judge's express finding that the prosecutor's conduct was negligent rather than intentional defeats that exception, so the second prosecution may proceed.
Why each wrong choice fails:
- A: This overstates the rule. Attachment of jeopardy is a necessary but not sufficient condition for the bar; defense-requested mistrials generally permit retrial. The Clause is not violated by every second trial after a sworn jury. (The Manifest-Necessity Misread)
- B: This misuses the manifest-necessity doctrine, which applies when a mistrial is declared over a defendant's objection. Patel moved for the mistrial, so manifest necessity is not the operative framework here. (The Manifest-Necessity Misread)
- D: This misstates attachment in a jury trial. In a jury trial, jeopardy attaches when the jury is empaneled and sworn — not when the first witness is sworn. The first-witness rule is for bench trials. (The Pre-Attachment Mirage)
What is the strongest basis on which the court should grant Liu's motion?
- A Blockburger same-elements analysis, because both charges arose from the same convenience-store incident.
- B Collateral estoppel under Ashe v. Swenson, because the prior acquittal necessarily resolved identity in Liu's favor. ✓ Correct
- C Cal. Penal Code § 656, because Liu was previously acquitted in another jurisdiction.
- D The Fifth Amendment's prohibition on multiple punishments, because she would otherwise face cumulative sentences.
Why B is correct: Robbery and assault with a deadly weapon each require an element the other does not, so under Blockburger they are not the 'same offense' and the bar against successive prosecutions for the same offense does not apply. But collateral estoppel — embedded in the Double Jeopardy Clause by Ashe v. Swenson — prevents relitigation of an ultimate fact necessarily decided in the defendant's favor. Because the only contested issue at the first trial was identity, and the jury necessarily found Liu was not the perpetrator, the prosecution cannot relitigate that fact to prove she committed the assault.
Why each wrong choice fails:
- A: Blockburger compares statutory elements, not the underlying conduct. Robbery and assault with a deadly weapon each have a unique element, so they are different offenses under the test, and the same-offense bar does not apply. (The Same-Conduct Decoy)
- C: Section 656 applies only when the prior prosecution occurred in 'another jurisdiction' (typically federal court or another state). Both prosecutions here are by the State of California in the same county, so § 656 has no role. (The California § 656 Switch)
- D: The multiple-punishments prong applies within a single proceeding, not across successive prosecutions. Liu has not been sentenced cumulatively; she faces a second trial entirely. The relevant prong is successive prosecution.
How should the California court rule on the motion?
- A Deny the motion, because under the dual-sovereignty doctrine the federal and state governments are separate sovereigns and each may prosecute.
- B Deny the motion, because the federal Hobbs Act and California § 211 each require proof of an element the other does not under Blockburger.
- C Grant the motion, because Cal. Penal Code § 656 bars a California prosecution where the defendant was acquitted in another jurisdiction for an act that was an element of the prior offense. ✓ Correct
- D Grant the motion, because the Fifth Amendment's Double Jeopardy Clause bars successive prosecutions by any government for the same underlying conduct.
Why C is correct: Federally, the dual-sovereignty doctrine (Gamble v. United States; Heath v. Alabama) would permit California to prosecute despite the federal acquittal. California, however, has by statute restricted that result: Cal. Penal Code § 656 bars a California prosecution where the defendant was previously acquitted or convicted in another jurisdiction for an act that was an element of the prior offense. The taking that supplied the federal Hobbs Act prosecution is the same act that supplies the § 211 charge, so § 656 bars the California information.
Why each wrong choice fails:
- A: This is the correct federal answer but wrong in California. Section 656 statutorily overrides dual-sovereignty within California, and the question is asked in a California court applying California law. (The California § 656 Switch)
- B: Blockburger analysis is irrelevant to the California § 656 question, which turns on whether the same act was an element of the prior offense — not on whether the statutory elements differ. The statute reaches further than the federal Clause does. (The Same-Conduct Decoy)
- D: The Fifth Amendment, as construed in Gamble, expressly permits successive prosecutions by separate sovereigns. The federal Constitution alone would not bar this prosecution; the bar comes from California statutory law, not the Clause.
Memory aid
'A-S-A-M' for what the Clause bars: Acquittal retrial, Second-prosecution after conviction, And Multiple punishments. For attachment: 'Jury Sworn / Witness Sworn / Plea Taken.' For same-offense: 'Blockburger — Each Element Unique.'
Key distinction
The single most-tested distinction is Blockburger's 'same elements' test versus a 'same conduct' or 'same transaction' test. Blockburger compares statutory elements in the abstract — if each crime has a unique element the other lacks, they are different offenses even if they arise from the same act. Wrong answers will frame the test as 'same conduct' or focus on overlapping facts rather than overlapping elements.
Summary
Double jeopardy bars retrial after acquittal or conviction and multiple punishments for the same offense, with 'same offense' defined by Blockburger's elements test, attachment timed to jury-sworn or first-witness-sworn, and California's Penal Code § 656 overriding dual sovereignty within California.
Practice double jeopardy adaptively
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Start your free 7-day trialFrequently asked questions
What is double jeopardy on the California Bar?
The Fifth Amendment's Double Jeopardy Clause, applied to the states through the Fourteenth Amendment (Benton v. Maryland), prohibits (1) a second prosecution for the same offense after acquittal, (2) a second prosecution for the same offense after conviction, and (3) multiple punishments for the same offense in a single proceeding. Jeopardy attaches in a jury trial when the jury is empaneled and sworn, in a bench trial when the first witness is sworn, and in a guilty-plea proceeding when the court accepts the plea. Two offenses are the 'same offense' under the Blockburger 'same elements' test (Blockburger v. United States): they are the same unless each statute requires proof of a fact the other does not. The dual-sovereignty doctrine permits successive prosecutions by separate sovereigns (federal/state, state/state), but the State of California by statute (Cal. Penal Code § 656) bars a California prosecution where the defendant has already been acquitted or convicted in another jurisdiction for an act based on the same conduct that was an element of the prior offense — a meaningful California deviation from the federal rule.
How do I practice double jeopardy questions?
The fastest way to improve on double jeopardy is targeted, adaptive practice — working questions that focus on your specific weak spots within this sub-topic, getting immediate feedback, and revisiting items you missed on a spaced-repetition schedule. Neureto's adaptive engine does this automatically across the California Bar; start a free 7-day trial to see your sub-topic mastery climb in real time.
What's the most important distinction to remember for double jeopardy?
The single most-tested distinction is Blockburger's 'same elements' test versus a 'same conduct' or 'same transaction' test. Blockburger compares statutory elements in the abstract — if each crime has a unique element the other lacks, they are different offenses even if they arise from the same act. Wrong answers will frame the test as 'same conduct' or focus on overlapping facts rather than overlapping elements.
Is there a memory aid for double jeopardy questions?
'A-S-A-M' for what the Clause bars: Acquittal retrial, Second-prosecution after conviction, And Multiple punishments. For attachment: 'Jury Sworn / Witness Sworn / Plea Taken.' For same-offense: 'Blockburger — Each Element Unique.'
What's a common trap on double jeopardy questions?
Treating dismissal-before-jury-sworn as a double-jeopardy bar
What's a common trap on double jeopardy questions?
Comparing the facts proved rather than the statutory elements under Blockburger
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