Double Jeopardy As A Legal Defense

Double jeopardy is a principle of law as well as a clause found within the 5th Amendment to the U.S. Constitution1 that bars the government from trying you more than once for the same crime.

However, the clause comes into play even before a jury or judge renders a verdict in your case.

It also bars further action on your case in certain circumstances.

Protections Under Double Jeopardy

All states have the prohibition against double jeopardy within their own constitutions or penal codes. In California, it is found in Penal Code Section 6872.

The double jeopardy clause contains 3 protections. It prohibits:

  1. Being prosecuted again after an acquittal for the same offense
  2. Being subjected to double convictions for the same offense
  3. The imposition of multiple punishments for the same offense

The purpose of the clause was to prevent a defendant from being subjected to undue stress and expense from having to defend himself multiple times and to prevent an innocent person from being found guilty after numerous attempts by the government.

Exceptions To Double Jeopardy

One major exception to the double jeopardy provision concerns state and federal courts. States and the federal government are known as “separate sovereigns”, similar to separate nations contained within a confederation. Each state is independent to some degree from the federal government although they give up certain rights to the federal sovereignty.

So, if a state court acquits a defendant on particular charges, the federal court can step in and re-try the defendant on the same offense3. Usually, the federal prosecutor will allege that the defendant violated certain federal civil rights of the victim. Such cases often appear when law enforcement officers cause fatal injuries to someone when questioning, detaining, arresting or investigating a crime and the state court has acquitted them of homicide or aggravated assault.

Multi-State Exception

Another exception is if a crime is commited in multiple states across state lines. A defendant may be prosecuted by both states for the same offense by the proper jurisdiction4. However, the defendant may not be prosecuted by multiple governmental subdivisions such as a city or a county in addition to a state prosecution.

Civil vs. Criminal

Double Jeopardy does not apply when the different actions are both in criminal and civil court. Civil actions address different areas of the law than criminal actions and require a lower standard of proof called preponderance of the evidence campared to the criminal standard of beyond a reasonable doubt.

When Double Jeopardy Applies

Double jeopardy applies earlier than when an acquittal or a conviction occurs. The following are circumstances when a defendant can assert double jeopardy as a defense:

When Trial Commences

Your trial begins when the jurors are sworn in. If you have a court trial, or the judge is the trier-of-fact, the trial begins when the first witness is sworn. A dismissal may occur after the trial begins when a prosecutor decides that there is insufficient evidence to convict you. If this happens, then the prosecution is barred from trying you again on the same or a necessarily included offense.

Mistrial or Discharge of Jury

A mistrial can trigger the double jeopardy defense but it rarely occurs. A judge would have to unnecessarily declare a mistrial or a discharge of the jury. The seminal case on double jeopardy in this regard is U.S. v. Perez5. Although it was decided nearly 200 years ago, it is still sound law. Perez declared that at times a judge must discharge a jury where there is a “manifest necessity” to do so or otherwise the ends of justice would not be served6. Usually, the court will point to prejudicial conduct by the defense or prosecution, in or outside the courtroom, where it would not be possible to continue to a verdict without injustice to one side. For instance, a juror who lied during voir dire might be sufficient to convince a judge to declare a mistrial if the lie was material or affected the juror’s impartiality. Another example is a judge deciding to disqualify himself because he feels he cannot be impartial.

For the most part, an appellate court will look to see if the judge exercised sound discretion in declaring a mistrial. Although it is assumed that a court will accept a defense of double jeopardy if the mistrial is declared without the consent of the defendant, the court looks to thePerez standard of ‘manifest necessity” in deciding if the defense will apply. If it applies, then the defendant’s objection to dismissing or discharging a jury will not prevent the government from re-charging and re-trying the defendant.

A hung jury is usually the reason to declare a mistrial and discharge the jury. This occurs when there the jury is unable to reach a unanimous verdict. A judge will usually implore the jury to keep trying until it becomes obvious that further attempts are futile. Even if a defendant objects to the judge’s decision, it does not automatically mean that double jeopardy now applies. The number of times a defendant is tried for the same defense following a hung jury in each case does not necessarily bar the government from re-trying the case, though various circuit or appellate courts have disagreed on this factor. It would stand to reason, however, that a defendant subjected to numerous trials would suffer unduly as a result.


An acquittal acts as a complete defense to being tried again for the same offense. Unlike the defense, the prosecution cannot appeal a not guilty verdict unless the court lacked jurisdiction to try the defendant.


Similar to acquittals, a conviction also acts as a bar to further prosecution for the same offense. For instance, the government may not attempt to try you again to see if a harsher penalty or multiple penalties would be imposed.


If a criminal case is dismissed on the merits of the case, then double jeopardy applies. However, the supreme court has held that dismissal of a case unrelated to the guilt or innocence of a defendant does not bar a future criminal prosecution7. There are different circumstances when dismissals take place:

  • For instance, a court may dismiss the charge against a defendant charged with the same crime as another defendant so that he or she may testify against the other defendant.
  • If a misdemeanor is dismissed for failure to prosecute the case or bring it to trial within the statute of limitations or in violation of the defendant’s right to a speedy trial, then double jeopardy is a defense. This does not apply if there was a felony violation that accompanied the misdemeanor charge.
  • However, if a felony is dismissed a second time for failure to bring the matter to trial within a certain or reasonable time, the double jeopardy defense can be raised.
Plea Arrangements

Once you and the court accept a plea arrangement, you may not be tried for that offense. Your and the court’s acceptance operates as a guilty plea, even to a lesser charge, and is a conviction. The government may not decide to charge you again for that offense.

Appeal of Conviction

If your conviction is reversed on appeal, it will be remanded to the trial court for a re-trial if the prosecution decides to do so. However, the prosecutor may not charge you with a greater offense than what was originally charged. For example, if you were found guilty of manslaughter at the first trial, the prosecutor cannot decide to now charge you with first degree murder. Because you were convicted of manslaughter, it is axiomatic that the jury rejected first degree murder so that you were essentially acquitted of that charge.

However, if the court in which you were tried did not have jurisdiction over you as determined by an appeals court, then your conviction would be considered void. In such a case, you could be tried again in a court that has jurisdiction over you and the offense for which you are charged.

Included Criminal offense

The government may not try you twice on a necessarily included offense that is similar to the one for which you were charged and acquitted. Some crimes contain elements that are part of other crimes, such as aggravated assault where the elements of simple assault are necessarily included. If you are acquitted of either, you cannot be prosecuted for the lesser or greater charge that was not part of the original complaint or indictment against you8.

Frequently Asked Questions

Question: I was found not guilty for vehicular manslaughter so why can I be tried in civil court for damages?

Response: Double jeopardy is not applicable in civil cases. Different standards of proof apply and you are not subject to incarceration if found civilly liable for causing someone’s death because of negligence or unlawful conduct. This was highlighted by the O.J. Simpson case where he was acquitted of double homicide in the deaths of his ex-wife and Ronald Goldman. The Goldman family sued Simpson in civil court following the not guilty verdict in criminal court and was awarded several million dollars by the jury.

Question: The judge dismissed my felony charges at a preliminary hearing so why can the prosecution re-charge me?

Response: Double jeopardy only applies when your trial begins. A preliminary hearing is not a trial so the government is free to re-charge you to see if a court at another preliminary hearing will find probable cause to have you tried in court. Usually, the prosecution will have additional evidence to offer.

Question: I was acquitted of one charge by a jury but they were unable to reach a verdict on another count. Can I be re-tried for that other count?

Response: Yes, if the judge declared a mistrial on the second count on the basis of “manifest necessity,” then you can be re-tried on that count alone so long as the second count or charge was not a necessarily included offense. A mistrial is usually declared if the jury is declared hopelessly deadlocked. In many cases, however, the prosecution will either decide to not re-try the case or will offer you a plea arrangement.

Question: I was charged with violating my parole. Why doesn’t double jeopardy apply:

Response: Conditions of parole or probation are not part of the original charge but are merely extensions of the original conviction.

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  2. California Penal Code 687 – Second prosecution for the same offense prohibited.  No person can be subjected to a second prosecution for a public offense for which he has once been prosecuted and convicted or acquitted. []
  3. United States v. Koon, 34 F.3d 1416 (9th Cir. 1994), aff’g 833 F. Supp. 769 (C.D. Cal. 1993), available at []
  4. Heath v. Alabama, 474 U.S. 82 (1985), available []
  5. U.S. v. Perez, 22 U.S. 579 (1824), available at []
  6. When are a mistrial and retrial double jeopardy? available at []
  7. United States v. Scott, 437 U.S. 82 (1978), available at []
  8. Blockburger v. United States, 284 U.S. 299 (1932), available at []