If a defendant is convicted of a crime at a trial, they may be able to seek a new trial. This would essentially restart the case in front of a new jury. While a motion for a new trial is hard to win, it can be successful if the defendant presents evidence of significant errors during the trial or new exculpatory evidence. Often, the standard for prevailing on these motions is showing that the defendant’s right to a fair trial was violated. The trial judge reviews these motions, rather than an appellate judge. Convincing the judge of their own error can be challenging.
Sometimes a motion for a new trial will succeed based on a serious injustice that arose during the trial. This might involve evidence of bias or prejudice by jury members, which violated the defendant’s right to an impartial jury. In other situations, a judge might grant a new trial based on an injustice if the judge or prosecution failed to respect the constitutional rights of the defendant. For example, they are entitled to confront the prosecution’s witnesses. Also, the prosecution generally cannot use the defendant’s decision to exercise their right to remain silent against them. In another example, the evidence may suggest that the defendant was prevented from testifying because of threats or manipulation. This also can justify a new trial.
New Trials Based on Legal Errors
If a mistake of law during the trial was sufficiently significant, the judge might grant a new trial. As discussed above, motions for a new trial are reviewed by the same judge who made the alleged error. While it might seem unlikely that the judge would acknowledge a mistake, some trial judges would prefer to grant a motion for a new trial instead of having their ruling overturned on appeal. Appellate courts usually give significant deference to trial judges, though.
Legal errors often relate to the admission or exclusion of evidence. These rules can be complicated, especially those related to hearsay. Sometimes a judge might make a mistake about whether an exception to the hearsay rule applies. However, the defense still would need to show that the error had a significant impact. If there was enough evidence to prove the prosecution’s case anyway, the judge probably will not grant a new trial.
New Trials Based on Exculpatory Evidence
To grant a new trial on this basis, the exculpatory evidence needs to be sufficiently significant to potentially change the outcome of the case. The defense must show that they were unaware of the information during the trial and that they could not have discovered it during the course of the trial. Again, if the prosecution could have obtained a conviction anyway, or if the evidence would not have added any new component to the defense, the judge probably will not grant this motion.
An example of exculpatory evidence that might justify granting a new trial is when the defense finds a witness who is central to their theory of the case. If the witness corroborates the defendant’s testimony, which previously lacked corroboration, this might alter the jury’s view of the defendant’s credibility and change their interpretation of the facts.
Getting the Process Started
In rare cases, a trial judge might order a new trial even without a motion by the defendant. More often, though, the defendant or their attorney will need to file a motion for a new trial. If the judge denies the motion, they have a right to appeal the denial.
It is important to know that the prosecution does not have a right to ask for a new trial. This would violate the principle of double jeopardy. (Read more here about this protection for criminal defendants.) The prosecution may be able to appeal a decision to grant a new trial.