For a jury to render a verdict in all federal felony cases and in 48 of the 50 states, the jury of 12 needs to be unanimous. If there is one lone holdout the jury is considered hung and no verdict is reached. The two states not requiring unanimity are Oregon and Louisiana where 10 of 12 is enough to acquit or convict (though Oregon still requires a unanimous vote to find defendants guilty of murder). Much has been written about the 10 of 12 rule in these two states, including its origins, current implications, and in a recent legal appeal by critics who argue the rule is unconstitutional by depriving citizens of equal protection under the law. The US Supreme Court declined to hear an Oregon case so the 10 of 12 rules remain in effect.

The origins of the less than unanimous rules are quite old. In 1898, Louisiana adopted its 10 of 12 verdict system in order to diminish the influence of black jurors on verdicts. Black defendants would be acquitted due to 1 or 2 holdouts, perhaps black jurors, and the State felt the 10 of 12 rule would facilitate more convictions. In 1933, a sensational murder trial in Oregon involving a Jewish defendant prompted voters to adopt the non-unanimous jury system. Oregonians at the time complained that too many immigrants were serving on juries and disrupting the status quo of historical Oregon juries. One holdout in the Oregon case kept the jury from agreeing on the most serious charges, prompting the Morning Oregonian newspaper to print the following on November 25 of 1933: “This newspaper’s opinion is that the increased urbanization of American life … and the vast immigration into America from southern and eastern Europe, of people untrained in the jury system, have combined to make the jury of twelve increasingly unwieldy and unsatisfactory.”

A defendant in Louisiana or Oregon charged with manslaughter, rape or arson for example, who has no chance of an acquittal must hope for three jurors to strongly fight for an acquittal as opposed to one (or two jurors where 11 votes suffice for conviction). But it is not simply a question of numbers; the jury dynamic in a 10 out of 12 jurisdiction is entirely different.

How does the 10 of 12 rule affect verdict decisions? Most significantly, deliberations are often cut short when the group knows it can achieve a verdict without having every member agree. For example, where unanimity is required, if ten jurors lean in one direction and two hold out, the ten will try and persuade the two (and vice versa if the two jurors have the motivation and strength to try and do so) with evidence presented at trial. This evidence will be reviewed and discussed, with jurors weighing in on whether they believe it was credible evidence, and why they either do or do not and what inferences can or cannot be drawn from the evidence. Jurors will spend time justifying their tentative vote, responding to jurors who disagree with them, and bringing up other angles that may not have been previously discussed.

Some of the best deliberations I have seen entail mock jurors in focus groups trying vigorously to persuade fellow mock jurors of their point of view. These arguments reveal how jurors think and how they weigh the evidence before them. Deliberations are supposed to be about expressing views, gauging the collective sentiment of the group, and using the powers of persuasion to try and come to a decision that speaks with one voice. If unanimity is ultimately not attained and a hung jury declared, there is confidence the jury was thorough and tried diligently to be unanimous. Unanimous verdicts can take days or in some cases weeks. Typically no stone is left unturned and the argumentation and debate going back and forth is richer. In everyday life it is not easy to get 12 people to agree on anything, so when 12 people do agree after deliberating it seems that the system worked.

Conversely, if 10 of 12 is acceptable, upon realizing there is a 10-2 split, the jury will feel they have reached a verdict so they will sign the verdict form and discuss the case no further. Understandably, the literature is replete with the idea that when jurors are told to be unanimous the deliberations are more thoughtful, thorough and accurate. When 10 of 12 is acceptable for a verdict, deliberations are more cursory.

Having worked both in the civil and the criminal area, I have seen the difference. Deliberations are indeed in greater depth when unanimity is required (mostly in the criminal cases I have worked on) than when a split verdict (10 to 2) suffices – a split more frequently allowed in civil litigation.