The general public might not know a lot about grand juries, but the closed-door panels figure prominently in the legal aftermath of the January 6 riot at the U.S. Capitol and efforts to overturn the 2020 presidential election results.

A grand jury subpoenaed the National Archives for all materials the agency gave to the House Select Committee looking into the events leading up to January 6. Justice Department prosecutors are working with a grand jury that is reportedly looking into former President Donald Trump’s role in efforts to reverse the election outcome. A grand jury in Fulton County, Georgia, subpoenaed members of Trump’s legal team during its probe into possible illegal interference in Georgia’s 2020 elections.

Mystery often surrounds grand juries because their work is, by law, conducted in secrecy.

“Washington, D.C., has been investigating the individuals who were responsible for the [January 6] break-in, but how much farther that goes and the extent to which they’re investigating Donald Trump or Donald Trump’s confidants, we only know of that, if at all, because either people told the press or they brought litigation resisting subpoenas,” says Bruce Green, a former federal prosecutor who is currently a professor at the Fordham University School of Law. “And even then, if one wanted to, you could file the litigation as a John Doe [unnamed person] if you want to preserve confidentiality.”

‘indict a ham sandwich’

Grand juries play a central role in the American justice system. They are tasked with listening to evidence presented by prosecutors and witnesses and then deciding, by a secret vote, whether there’s enough evidence to charge a person with a felony, which is any criminal offense punishable by at least one year in prison.

Grand juries are required in federal felony prosecutions, and many U.S. states have adopted a similar system. However, in some states, prosecutors can also present their evidence to a judge, who then decides whether someone can be charged with a crime.

Federal grand juries are made up of 16 to 23 members. At least 12 jurors must agree before an indictment — a formal charge — can be brought. Grand jurors are selected from the same pool of ordinary citizens who serve as trial jurors. They are identified from public records such as driver’s licenses and voting registries. Grand jurors serve from 18 to 36 months, usually meeting a few times a month, and have the power to question witnesses and issue subpoenas.

“The grand jury system is important in terms of deciding who’s going to face criminal charges, but it’s also important for involving citizens in the criminal justice system,” says Peter Joy, a law professor at Washington University in St. Louis. “The origins of the grand jury system are based on, in a sense, a certain degree of trying to keep the government honest.”

Grand juries were originally conceived as a safeguard against government power, which is why the Founding Fathers wrote them into the U.S. Constitution. But former federal prosecutor Green isn’t convinced the so-called “people’s panel” fulfills that function in a meaningful way.

“If the original idea of the Founding Fathers was, as I believe it was, to be a restraint on government power … it’s probably not a very effective tool to protect people from prosecution overreaching,” Green says. “And there’s a pretty significant risk that, if the prosecutor gets it in their head that somebody’s guilty, they can achieve an indictment whether the person is guilty or not.”

Grand juries rarely decline to indict. In 2010, government statistics showed that federal grand juries brought charges more than 99% of the time. In 1985, a New York judge famously said that prosecutors have so much influence over grand juries that they could convince jurors to “indict a ham sandwich.”

High stakes

While the grand jury might be a rubber stamp in most cases, the panel is more likely to play a more meaningful role in cases that draw widespread public attention, Joy says.

“I think it’s very likely that prosecutors in presenting the evidence to the grand jury most likely tried to present more evidence than they might in a typical type of case and presented in a way that would be balanced,” he says.

Some states require prosecutors to show evidence that the accused might be innocent. However, federal prosecutors are not required to do so.

“The higher the profile the accused has, the greater the likelihood is that the prosecutor really wants to feel that he or she has a solid case, and they’re going to want to test out the evidence in a way that would give them increasing confidence in the case that they have,” Joy says.

“Because the stakes are high, a smart prosecutor — if there is some contrary evidence that might put into question guilt or innocence — they’re likely to use the grand jury as a vetting process for that.”

Green expects several grand juries to consider potential charges against people accused of breaking into the Capitol Building on Jan. 6, 2021. The high volume of cases could be too much for one grand jury to consider. However, that might not hold true in related cases higher up the food chain.

“If you’re looking at a number of people in the Trump orbit who may have been working together before January 6 to plan the break-in, then all the evidence is going to be related, and they’re all going to be in a relationship, and you’re going to want to have one grand jury look at everything because you want them to see all the evidence,” Green says.