A mistrial is a term that refers to a trial that is ended before its conclusion because of some error or problem with the trial itself. A mistrial must be declared by the judge overseeing the trial, and renders the entire trial invalid. This is most likely to occur when the judge feels that the problem makes it impossible to ensure a fair verdict is reached. This allows the parties to start over again with a new trial if they want, though the circumstances may lead the parties to not request a new trial. To explore this concept, consider the following mistrial definition.

Definition of Mistrial


  1. A trial that is terminated before its natural conclusion, due to some error or catastrophic circumstance.


1620-1630       Anglo French

What is a Mistrial

In the American judicial system, great pains are undertaken in order to ensure that trials, whether civil or criminal, are fair and impartial. This entails following a great many rules and procedures. Sometimes mistakes are made, rules are broken, and unforeseen events take place.

When such an issue occurs that is serious enough to convince the judge that a fair trial or verdict is unlikely to result, he or she may cancel the trial, declaring it a “mistrial.” Declaration of a mistrial does not necessarily end the matter entirely, as the parties may request a new trial in most cases.

Reasons for a Mistrial

There are a number of reasons a judge may declare a mistrial, most of which involve a fundamental error in the proceedings that cannot be overcome by special instructions given to the jury. Reasons for a mistrial may include such things as:

  • Lack of court jurisdiction over the subject
  • Error in, or unfair, jury selection
  • Inadmissible evidence being allowed, or presented in opening or closing remarks
  • Unfair comments made within the jury’s hearing
  • A deadlocked, or “hung” jury (one of the most common reasons for a mistrial)
  • Death or long-term illness of a judge, attorney, juror, or even witness
  • Misconduct by an attorney, or the jury

While a judge may decide on his own to declare a mistrial, an attorney may also request that the trial be ended because of some error or prejudice. When determining whether to declare a mistrial, the judge must evaluate whether or not an error or catastrophic problem has occurred, and whether it has prejudiced the proceedings so much as to make coming to a fair conclusion a futile effort. In any example of mistrial, because of the time, effort, and expense, as well as other factors, involved in presenting the trial to that point, a judge’s power to declare a mistrial should only be used when absolutely necessary.

Mistrial for Juror Misconduct

Having a jury of regular people hear the facts of a case, deliberate on them, and decide whether a person accused of a crime is guilty – or which side in a civil lawsuit wins – is the cornerstone upon which the judicial system is built. The parties put a great deal of effort into choosing jurors they believe will be fair and impartial in rendering their decisions. Once a jury has been chosen, there are rules to which the jurors must adhere – these are designed to maintain their impartiality, and to ensure a fair trial.

The term juror misconduct refers to a juror’s actions that violate any of these rules. Actions that may be considered juror misconduct, and result in a mistrial include:

  1. A juror communicating with someone outside the trial or case, including friends, family members, witnesses, attorneys, judges, and bailiffs.
  2. A juror bringing into the jury room information or evidence about the case that he discovered himself.
  3. A juror conducting experiments on theories of the case, outside the court’s presence.
  4. A juror trying to convince another juror to decide one way or the other.

The purpose of these rules, which isolate the jurors and restrict information they are able to see and hear, is to prevent bias, and to ensure the jury makes its decision based solely on the information provided at trial. The immediate availability of information in today’s high-tech world makes limiting outside information and contact a difficult thing to enforce. Not only can people readily find information about the case they are judging, but they can look up information on general facts. Doing so, however, is against the rules for jurors.

For example:

John is being tried for aggravated assault, a violent crime that is a felony, and carries a stiff penalty. During the trial, John’s attorney presents evidence that John has a mental illness, called “schizoaffective disorder,” which causes violent behavior. Trying to understand this disorder further, juror Anne searches for information online, after returning home one day.

Although her intent is to become more informed, and to perhaps share these insights with the other jurors so they can make an informed decision, Anne has violated the jury rules. In this example of mistrial circumstances, the trial may be terminated because of juror misconduct.

Mistrial for Prosecutorial Misconduct

In criminal matters, the prosecutor is responsible for determining who should be held responsible for a crime that has been committed. This includes overseeing an investigation to build a case, then presenting all of the evidence gathered in an attempt to convince a jury of the accused person’s guilt. Within this framework, prosecutors are expected to act with professionalism and competence, as well as to adhere to the laws and rules of court that govern the trial process.

Prosecutorial misconduct refers to a situation in which a prosecutor breaks a law, or the code of professional ethics, during prosecution of the case. The U.S. Supreme Court has recognized the seriousness of such situations, and Supreme Court Justice Alexander George Sutherland defined prosecutorial misconduct as “overstep[ing] the bounds of that propriety and fairness which should characterize the conduct of such an officer in the prosecution of a criminal offense.”

Prosecutorial misconduct may take many forms, such as:

  • False arrest
  • False confession
  • Plea bargaining abuse
  • Falsified evidence
  • Using intimidation (to coerce a confession, testimony, or other)
  • Threatening public officials
  • Surveillance abuse
  • Subornation of perjury (persuading a person to commit perjury)
  • Failure to disclose exculpatory evidence (evidence that favors the defendant, or which tends to exonerate the defendant of guilt)

The Effect of a Mistrial on Double Jeopardy

The Fifth Amendment to the U.S. Constitution protects people from being put on trial for the same offense again and again. Referred to as the “Double Jeopardy Clause,” this clause states:

“…nor shall any person be subject for the same offence to be twice put in jeopardy of life and limb …”

The purpose of this constitutional protection is to prevent the government, which has great resources, from making repeated attempts to convict someone for an alleged offense. This brings the question, then, of how the declaration of a mistrial fits in with double jeopardy. Once a jury has been chosen, jeopardy attaches, which means that the defendant has a right to expect his trial to continue and come to an end with a verdict, without interruption. Whether or not the prosecution can retry the defendant at a later date is a little complicated.

When a mistrial is declared at the defendant’s request, or with his consent, jeopardy does not end, making it possible for the prosecution to initiate another trial. When a trial is prematurely ended without the defendant’s consent, certain circumstances must exist if the prosecution wishes to hold another trial. Declaration of a mistrial does not prohibit later prosecution in these circumstances:

  • Deadlocked, or “hung” jury – a jury that cannot reach an agreement on the defendant’s guilt or innocence.
  • Dismissal for a procedural error
  • Dismissal for unforeseen events, such as a death

Even if a mistrial was declared because of a procedural error by the prosecution or the judge, the defendant may be retried, unless the prosecutor or judge acted in bad faith. In fact, if the prosecutor’s or judge’s actions were intended to goad the defendant into asking for a mistrial himself, double jeopardy may apply, protecting the defendant from a second trial.

Mistrial Example of Jury Misconduct

In June, 2015, 24-year old Vincente Delgado Jr. was arrested after being accused of holding a woman against her will, and raping and sodomizing her. When police searched Delgado’s home, they discovered photos and videos depicting his actions on the night in question. Delgado was charged with the crimes of first degree rape, kidnapping, first degree sexual assault, first degree sexual offense, misdemeanor sexual battery, identity theft, larceny, and financial card fraud.

During the difficult trial, in which many sexually graphic photos and videos were presented as evidence, two jurors were seen and photographed in an animated discussion outside the courtroom, which is against the rules. Delgado’s attorney, Tim Oswalt, asked the judge to declare a mistrial due to jury misconduct. In fact, one of the jurors had admitted to discussing the trial outside the court, which the judge had specifically told the jurors not to do prior to each break.

The judge did declare a mistrial, and the juror who did not admit what he had done was fined $200, and held in jail for three days, for contempt of court. In this example of mistrial for jury misconduct, the defendant can be put on trial again.

Related Legal Terms and Issues

  • Bad Faith – Fraudulent deception; malicious or intentional failure to perform a contractual obligation or other duty.
  • Coerce – To persuade by force, intimidation, or authority.
  • Contempt of Court – A willful act of disobedience to an order of the court; deliberately being rude or disrespectful to the judge or the court.
  • Exculpatory Evidence – Evidence in a criminal trial that is favorable to the defendant, or which tends to exonerate the defendant.
  • Jurisdiction – The legal authority to hear legal cases and make judgments; the geographical region of authority to enforce justice.
  • Jury – A group of people sworn to render a verdict in a trial, based on evidence presented.
  • Perjury – The willful telling of an untruth, or giving of false testimony, after having taken an oath.
  • Plea Bargain – An agreement between the prosecutor and defendant in which the defendant agrees to plead guilty to some of the charges, or a lesser charge, in exchange for a reduced sentence, or some other concession by the prosecution.
  • Verdict – A decision, opinion, or judgment in a civil or criminal trial.