Here is my shitty discussion (which I hope answers Z's question):
The jury system has been around since the 8th century, and can be seen even as far back as 500BC, although the modern jury was developed around the 11th century in England under Henry II. Up until very recently, a twelve person jury had to unanimously decide whether a person was guilty or innocent. Aside from a few judicial powers to maintain fairness and to secure justice, the word of the jury was final, and the unanimous verdict was incredibly important, and a failure to reach a conclusion could lead to a retrail. Recently however, jurisdictions have moved towards supermajority verdicts, either 11-1, or 10-2.
The main case for majority verdicts is time and money. If the jury tells the court that “we don't know” or “we can't agree”, a retrial will be needed. Such an event would be very expensive for the courts, time consuming for all the participating parties, and would be unfair on the accused, who will have to sit through another court session in incredible anxiety.
Many jurisdictions have decided to streamline courtroom efficiency by implementing a majority verdict. A hung jury is usually due to a rogue juror, someone who is adamant towards one verdict and will not consider the other, and who will not participate in jury deliberations and discussions. A study in Australia found that 33% of hung jurys were a result of a rogue juror. A quite unique argument against unanimous verdict is that a hung jury, which leads to a retrial, will allow the prosecution or the defence to reshape their arguments, and will, some say, lead to an unfair trial, though to how much extent, it is uncertain.
Another reason that majority verdict supporters put forward in their case is that the unanimous verdict creates an incentive for jury tampering. By controlling even one juror, a wealthy or powerful person or organization could taint verdict deliberation in support of their side, and make a mockery of the court system.
Also, a point that is sometimes brought up, is that a single juror who stands by his or her opinion on the verdict (it must be mentioned that he or she is not necessarily a rogue juror, or a tainted one), is often bullied into conforming to the rest of the jury's view. Like everyone else in the courtroom, the jury would rather finish up quickly and be on their way home, although in NSW law, the law proclaims “Jurymen should not be led, from a desire to acquiesce, or to avoid eccentricity, or to save time and trouble, to represent themselves as holding views which they do not hold.”.
However, a large amount of legal professionals, including lawyers and judges, are against majority verdicts, the main reason for which is the standard of proof in all criminal cases, “beyond reasonable doubt”. Supporters of the unanimous verdict claim that a majority verdict is a clear breach of the criminal court standard of proof. They argue that having even one juror debating the verdict of the rest is enough to cast doubt. If the juror is reasonable, then it is not beyond reasonable doubt. If the juror is not, he or she would have been screened out during the selection process. The argument that the unanimous verdict leads to ineffective deliberations is often seen as inaccurate.
Requiring only a majority verdict could also limit the amount of deliberation going on within the jury, and the amount of analysis and examination of testimony and evidence. Jury dynamics are very important within the court system.
Rejection of unanimity is also seen as immoral, especially when the stakes are as high as life imprisonment, or in some jurisdictions, death, and most people find it unjust when money is held higher than a persons life.
Since the jury is meant to represent society as a whole, there are fears that a decision with even a single shred of opposition will not be fully accepted by society.
The debate between the two sides will undoubtedly be a long and hard one, with both sides presenting good points on behalf of the nature of the legal system, and the best way to achieve a fair system that will represent all sides equally and justly.
