A jury is required to make a unanimous or near unanimous verdict on a case. In some circumstances, jurors are unable to agree on a verdict due to a complete division in opinion and judgment. When this occurs, it is said to be a "hung jury".
A trial jury duly selected to make a decision in a criminal case regarding a defendant's guilt or innocence, but who are unable to reach a verdict due to a complete division in opinion.
When a jury has been given an adequate opportunity to deliberate and is unable to reach a verdict, a retrial takes place at the discretion of the prosecution. The subsequent trial does not constitute a violation of the constitutional prohibition of double jeopardy.
Duhaime Legal Dictionary
A jury is required to make a unanimous or near unanimous verdict.
When the jurors, after full debate and discussion, are unable to agree on a verdict and are deadlocked with differences of opinion that appear to be irreconcilable, it is said to be a "hung jury".
The result is a mistrial.
The office of the Attorney General for California defines a hung jury as: "A hung jury occurs when jurors cannot unanimously agree on a verdict of either guilty or not guilty, followed by the judge declaring a mistrial. The case may or may not be retried, at the discretion of the prosecutor."
n. slang for a hopelessly deadlocked jury in a criminal case, in which neither side is able to prevail. Usually it means there is no unanimous verdict (although in Oregon and Louisiana 10 of 12 jurors can convict or acquit). If the jury is hung the trial judge will declare a mistrial. A new trial from scratch, with a new jury panel, is required. The prosecutor can decide not to re-try the case, particularly if a majority of the jury favored acquittal.
Lect Law Library
A jury that is unable to reach a verdict which, if it persists, usually results in a mistrial being declared by the court.
In such a situation the case may be retried, generally at the discretion of the prosecution if criminal. In such a situation a retrial does not constitute double jeopardy.
In the interests of justice and judicial economy most courts will attempt various means to allow/persuade a jury to continue deliberating and only declare a mistrial when certain the jury is incapable of reaching a verdict.
A hung jury or deadlocked jury is a jury that cannot agree upon a verdict after an extended period of deliberation and is unable to change its votes due to severe differences of opinion.
In the United States, the result is a mistrial, and the case may be retried. Some jurisdictions permit the court to give the jury a so-called Allen charge, inviting the dissenting jurors to re-examine their opinions, as a last ditch effort to prevent the jury from hanging.
Juries in criminal cases are generally, as a rule, required to reach a unanimous verdict, while juries in civil cases typically have to reach a majority on some level. In jurisdictions giving those involved in the case a choice of jury size (such as between a six-person and twelve-person jury), defense counsel in both civil and criminal cases frequently opt for the larger number of jurors. A hung jury is generally regarded as the next best thing to an acquittal. A common axiom in criminal cases is that "it takes only one to hang," referring to the fact that, in some cases, a single juror can defeat the required unanimity.
If a defendant has been found guilty of a capital offense (one that, because of aggravating factors like rape during a premeditated murder, could result in the death penalty if the person is eligible- over 18 at the time of the offense and not mentally retarded), then the opinion of the jury must be unanimous if the defendant is to be sentenced to death.
One proposal for dealing with the difficulties associated with hung juries has been to introduce supermajority verdicts. This measure would allow juries to convict defendants without unanimous agreements amongst the jurors. Hence, a 12-member jury that would otherwise be deadlocked at 11 for conviction and 1 against, would be recorded as a guilty verdict for the defendant. The rationale for majority verdicts usually includes arguments involving so-called 'rogue jurors' who unreasonably impede the course of justice. Opponents of majority verdicts argue that it undermines public confidence in criminal justice systems and results in a higher number of individuals convicted of crimes they did not commit. Currently two states, Oregon and Louisiana, do not require unanimous verdicts in criminal cases.