Mistrial: Definition & Motions

Instructor: Elisha Madison

Elisha has Master's degree in Ancient Celtic History & Mythology, as well as a Bachelor's in Marketing. She has extensive experience creating & teaching curricula in college level education, history, English, business and marketing.

A mistrial is where a trial is ended prior to a verdict being read. This lesson discusses the full meaning of a mistrial as well as why it can happen.


Say you have a juror that has been secretly influenced by the defense. They are being paid off to fight for the defense's freedom. Sounds like a famous book or movie right? Well this is also a prime example of why a mistrial would occur.

A mistrial is a trial that has been prematurely ended prior to the verdict being read. This can happen for a multitude of reasons:

  • Illness or death of prosecution/defense/judge/jury
  • Tampering of evidence
  • Dropping out of witnesses
  • Evidence or outburst seen by the jury that will influence them, even if asked to disregard
  • Inability to find an unbiased jury
  • Suspicious behavior or criminality of prosecution/defense/judge/jury
  • Prejudicial behavior by prosecution/defense/judge/jury

Another main reason for mistrials are hung juries. These are juries that have been unable to come to consensus on whether the defended is guilty or not guilty. In a jury of 12, this means 10 people must have a consensus, in a jury of 6, all of them must agree. If not, then a motion can be filed to declare a mistrial.

Justice For All


In law, a motion is essentially a question from the lawyers to the judge. A motion can be used in a variety of ways:

  • Motion to Discover - Request information from the opposite legal team
  • Motion to Dismiss - Request to dismiss the case altogether, perhaps because new evidence supports innocence.
  • Motion for Summary Judgement - This only pertains if the defendant admits their crime, and the defense is just looking to get judgement, prior to even the trial starting.
  • Motion for Mistrial - Request a mistrial

In a trial, the judge can declare a mistrial for the reasons above, and the prosecutor and defense can request a mistrial. If either does, the judge has to determine if there is reason enough to do so. If not, then the trial will go on.

When asking for a mistrial the prosecutor or defense must address the reasoning behind why the misconduct or issue has affected the trial to the point that they no longer want it to continue. For example, a defense attorney could ask for a mistrial if a juror burst out accusing the defendant of other crimes. This shows that there is not an impartial jury, so it would likely be an approved motion.

Depending on the crime and the situation however, a mistrial can mean the defendant cannot be retried due to double jeopardy.

Double Jeopardy

Double jeopardy is a part of the fifth amendment of the constitution. It protects people from the emotional and financial trouble of being tried over and over for the same act.

The problem with mistrials is that it can bring into account double jeopardy, which means the defendant cannot be tried for the same crime twice. However, there are a few rules that will allow for a retrial.

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