Grand juries make the news in almost every major federal case. There’s a good reason for that: the Fifth Amendment to the United States Constitution, which says, in part, “No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a grand jury.”

But what is a grand jury? And why are they there?

WHAT IS A GRAND JURY?

A grand jury is considered the "sword and the shield" of the judicial system. A shield because presenting a case to the grand jury before proceeding to trial prevents prosecutors from trying overzealous, politically motivated, or weak cases.

The sword is in reference to the grand jury’s broad investigative powers. They have the power to issue subpoenas, compelling witnesses to testify under oath (barring application of the more famous part of the Fifth Amendment) and making people produce necessary documents. That’s why going before a grand jury doesn’t necessarily mean a crime has occurred or that an indictment is coming; it may just be needed to help the investigative process along.

Their proceedings are also secret. No judges are present and usually the only lawyer in the room is the prosecutor. It’s intended to make witnesses willing to testify and, from the defendant’s side, it means that they’re not damaged by allegations that aren’t strong enough to make it past the grand jury.

SO WHAT IS THE ORIGIN OF THIS BIZARRE JURY?

Historians debate whether the Assize of Clarendon was a revolutionary document or merely a codification of a preexisting tradition [PDF]. Either way, in 1166 English King Henry II enacted the Assize of Clarendon, which required a group of “lawful men” to gather periodically to inform the King’s justices of the names of people who the community suspected had recently committed a robbery/theft or murder in the area (this would later be expanded to other crimes). According to the assize, “he who shall be found through the oath of the aforesaid persons to have been charged or published [as a criminal] ... shall be taken and shall go to the ordeal of water.”

While often described as essentially an early neighborhood watch program, historians credit this assize with splitting the process of indictment and trial [PDF], a critical step to the modern grand jury.

In 1215 (the same year as Magna Carta) the Fourth Lateran Council of Pope Innocent III banned priests from giving blessings in trials by ordeal, forcing the entire legal system of England to evolve.

With the disappearance of trials by ordeal, the modern idea of trial by jury began appearing. It soon became obvious that having the same people accuse someone and then convict them was at best awkward, so the two responsibilities began splitting into two independent juries: the accusing jury and the trial jury [PDF]. In 1368, Edward III formalized the grand jury system and thus the grand jury became the "sword."

The most important moment for the "shield" came in the 1680s, during the trials of the Earl of Shaftesbury and Stephen Colledge. Shaftesbury and his ally Colledge had been attempting to remove the Catholic James (future King James II) from the line of succession to the throne by having King Charles II legitimize one of his illegitimate Protestant sons. King Charles II reacted by dissolving Parliament, and soon arrested Shaftesbury and Colledge, then charged them with treason.

The London grand jury, though, populated by people who agreed with Shaftesbury, held firm and refused to indict either of them. The foreman of the Colledge grand jury was even sent to the Tower of London (although some have argued it was for an unrelated charge). This case was a watershed moment because it showed the grand jury was able to stand up to the king and deny even a trial. The grand jury was becoming a powerful tool against the government. Sadly though, King Charles II moved the Colledge trial to Oxford, found a more sympathetic grand jury, and executed Colledge while the Earl of Shaftesbury fled the country.

The grand jury would continue to be a part of English law until it was eliminated for most cases in 1933, and abolished completely in 1948. But grand juries would continue in one of England’s former colonies ...

THE GRAND JURY IN COLONIAL AMERICA

The American equivalent of the Shaftesbury/Colledge case was the case of Peter Zenger in the 1730s. Zenger was the printer of The New York Weekly Journal, which was publishing articles against New York’s Governor, William Cosby. Cosby decided to arrest Zenger for printing seditious libel, but two separate grand juries refused to issue an indictment. Cosby then used a different legal process to go around the grand jury, but eventually the trial jury also refused to convict Zenger of seditious libel.

Both the attempts at prosecuting someone solely for printing a paper and the attempts at getting around the decision of the grand jury enraged colonists, and although it didn’t create an important precedent, the case helped solidify the view Colonists had toward an independent press and an independent grand jury.

The grand jury soon became a bludgeon wielded by the colonists against unpopular British acts. Grand juries “all but nullified the law of seditious libel in the colonies” and a Boston grand jury even refused to indict the colonists behind the Stamp Act riots. Other unpopular laws became effectively unenforceable [PDF]. Grand juries were coming to be viewed as a critical part of the judicial system; a way to protect against a tyrannical government. So when it came time to write the Bill of Rights, they were a natural inclusion.

THE GRAND JURY IN AMERICA

In the United States, grand juries would exhibit such independence that the term “runaway grand jury” appeared to describe grand juries that didn’t follow the prosecutor’s orders. Perhaps the most extreme application of the investigative powers occurred in Minnesota. In 1902, Minneapolis mayor Albert Alonzo Ames was widely considered corrupt, but no one was willing to go after him or his ‘gang’ until Hovey Clarke was appointed the foreman of a grand jury. According to a 1903 McClure’s Magazine, “[Clarke] did not want to be a grand juryman, he did not want to be a foreman; but since he was both, he wanted to accomplish something.”

And what he did was bring down the mayor. He won over his grand jury, then when the prosecutor was unwilling to bring down Ames, he excused the prosecutor. Next he used the power of the grand jury to hire local detectives. According to McClure’s, the first batch of detectives were talkative and discussed the case with police. While police were watching those detectives, Clarke hired a second set of detectives to actually investigate. He even personally went to the jail to talk to criminals trying to get someone to flip. This case became national news and demonstrated the power of the grand jury (although after fleeing, getting captured, being convicted, and having that conviction overturned, Ames would go free).

Today, most states still have a grand jury, but their application varies widely. Since they’re enshrined in the Fifth Amendment, it's their role as the sword and the shield in federal cases that gets the most attention.

In recent years, there has been criticism that the ‘sword’ power of the grand jury has been overused while the ‘shield’ power has been diminished, turning the grand jury of today into essentially a rubber stamp for prosecutors.

Hawaii has attempted to remedy this with the creation of the Grand Jury Legal Advisor (GJLA) or Grand Jury Counsel. In traditional grand juries, the only lawyer in the room is the prosecution, which could lead to a conflict between the prosecutor providing legal advice and hoping for an indictment. The purpose of the GJLA is to restore some of the ‘shield’ function by giving the grand jury an independent advisor who can inform them of their rights and powers. According to Thaddeus Hoffmeister of the University of Dayton, “the GJLA strengthens the traditional role of the grand jury as a shield against unwarranted government accusations while still permitting grand jurors, prosecutors, and witnesses to perform their long-established functions.” [PDF]

It’s just another step in the evolution of the modern grand jury.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.