I don't think juries have the role that you imply. Their job is to decide which of the evidence is reliable. The judge's job is to decide what's legal. The court proceedings are steered by the judge to the evidence that relates to actual illegal stuff, then they decide whether they believe it. There have been cases where juries take the law into their own hands (https://en.wikipedia.org/wiki/Jury_nullification) but these are sufficiently rare that legal scholars get exercised over it.
Biting the hand that feeds IT
