The jury was an essential safeguard of liberty long before the American Revolution. British courts guaranteed the independence of criminal trial juries in 1670, in a case concerning four jurors who had acquitted William Penn for illegally preaching about his Quaker beliefs. Those jurors were imprisoned for their “not guilty” verdict because they had ignored the trial judge’s instructions to vote for Penn’s conviction. An English appellate court released the jurors from prison, establishing the principle that juries cannot be punished for bringing in the “wrong” verdict. The freedom of American jurors to vote according to conscience can be traced to that landmark precedent.
Early American jurors frequently refused to enforce the acts of Parliament in order to protect the rights of individuals. In 1735 a New York jury acquitted John Peter Zenger of seditious libel for publishing criticisms of a colonial governor, believing that Zenger had a right to print the truth. That jury had to ignore the instructions of the trial judge because it had been instructed that truth was no defense to the charge of seditious libel. We can thank independent juries for helping to establish freedom of the press on American soil.
Jurors in early America knew that if a criminal law was unjust, they could — and should — refuse to enforce it. They could vote their conscience, and as free citizens they were expected to do so. Thomas Jefferson wrote, “I consider trial by jury as the only anchor ever yet imagined by man, by which a government can be held to the principles of its constitution.” John Adams said, “It is not only [the juror’s] right, but his duty … to find the verdict according to his own best understanding, judgment, and conscience, though in direct opposition to the direction of the court.”