Immunity for witnesses is a key tool of prosecutors, whether they’re charging Trump or other alleged criminals – here’s how it works and what the limits are

A protester walks past the E. Barrett Prettyman U.S. District Court House in Washington, on August 1, 2023. Anna Moneymaker/Getty Images

At the heart of the alleged scheme for which Donald Trump was indicted on Aug. 1, 2023, was a fake electors plot designed to help him hold onto power after losing the 2020 presidential election.

In the U.S., people known as electors from each state and Washington, D.C., elect the president based on the popular vote.

According to the four-count indictment, Trump and two of six unnamed co-conspirators pulled together fraudulent slates of electors in seven key states in an attempt to subvert the real electors who were obligated, based on results of the popular vote, to cast ballots for Joe Biden. The fake electors cast fraudulent ballots for Trump.

This latest indictment represents the most serious charges against Trump yet.

In Fulton County, Georgia, where there is an investigation into alleged fake electors underway, a court filing indicates that District Attorney Fani Willis granted immunity to eight fake electors. And it’s possible that special counsel Jack Smith acted similarly in the federal probe. Based on anonymous sources, CNN reported that Smith compelled at least two fake electors to testify before a Washington, D.C., grand jury by giving them limited immunity.

The Conversation U.S. asked legal scholar William Ortman, an associate professor of law at Wayne State University, to explain how immunity and limited immunity work.

Special counsel Jack Smith arrives to give remarks following the Aug. 1, 2023, indictment of former President Donald Trump.
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What does it mean when a witness is granted immunity?

It depends on what kind of immunity we’re talking about. There are two basic types, which lawyers refer to as transactional immunity and use immunity. It’s easier to think of them as full immunity and limited immunity.

Full immunity is just what it sounds like. When a prosecutor grants a witness full immunity for an offense, she cannot thereafter prosecute the witness for that offense. Full immunity is tantamount to a “get out of jail free” card.

Limited immunity is more complicated. When a prosecutor grants a witness limited immunity, she can still prosecute the witness. But she can’t use the witness’s immunized testimony, or evidence that comes from it, against the witness.

Why would a prosecutor give a witness immunity?

Prosecutors grant immunity when they want testimony from someone who has refused. Generally, the government can compel testimony from anyone with information about a case.

The catch is that witnesses have a right under the Fifth Amendment to refuse to answer questions that could be self-incriminating. That puts prosecutors in a bind, particularly when they want information that is in the hands – or the minds – of people who participated in the activity they are seeking to prosecute.

Immunity gives prosecutors a way out. If a person has immunity, then by definition their testimony cannot incriminate them. That’s why if a witness has been granted immunity and refuses to testify, they can be held in contempt and sent to jail.

What does a witness get out of immunity?

It again depends on what kind of immunity we’re talking about. For a witness concerned about being charged with a crime, the benefits of full immunity are obvious. Limited immunity is less attractive to defendants, but it is often still appealing. That’s because it can be difficult for prosecutors to establish that they obtained evidence independent of immunized testimony, so limited immunity still offers witnesses some protection against future prosecution.

There are, however, hazards to testifying under a grant of immunity. One is that immunity typically does not cover perjury. So if an immunized person testifies and lies, or if the prosecutor just thinks they lied, they could be charged with a crime after all.

Beyond the risk of a perjury charge, testifying often means that a witness must provide information that could send a friend or ally to prison. It also means that the witness will be cross-examined by a defense lawyer, who will likely try to convince the jury that the witness is lying. There is also the possibility that the defendant or his associates, or both, might retaliate against the witness outside of the courthouse.

Is immunity negotiated between prosecutors and witnesses? How is it determined whether a witness gets full or limited immunity?

The government can negotiate immunity with a witness, but it doesn’t have to. When immunity is negotiated, it looks a lot like a plea agreement, except that the potential defendant doesn’t plead guilty to a crime. Immunity deals can get complicated, but the basic terms are pretty simple: The government agrees that it will not prosecute the person, which is full immunity, or that it will not use the person’s testimony against them, which is limited immunity, while the person agrees to cooperate in some way, often by testifying.

That said, the government can grant immunity to compel a witness’s testimony, even if the witness objects. That makes sense when you recall that the primary function of immunity is to overcome a witness’s right to remain silent. Whether a witness receives full or limited immunity in those situations is determined by statutes and state constitutions. In the federal system and some states, the prosecutor merely has to grant limited immunity to compel testimony. In other states, though, prosecutors can compel a person’s testimony only by granting full immunity.

It’s possible that special counsel Jack Smith granted immunity to fake electors or co-conspirators in the federal probe of former President Donald Trump.
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Is there a difference between state and federal immunity?

Some states are more generous than others, or than the federal government, in granting full rather than limited immunity. Beyond that, there are various procedural differences between state and federal immunity that can sometimes be important. But on the major points, there aren’t many glaring differences between how witness immunity works in the federal and state systems.

Can granting immunity in one jurisdiction make the job of a prosecutor in another jurisdiction harder?

Absolutely, and that is why federal and state prosecutors often coordinate. When a witness testifies in a state proceeding pursuant to a formal immunity grant from a state prosecutor, their testimony can’t be used against them in federal court either. In other words, the person has limited immunity in federal proceedings. And it works the same way in reverse. When a person testifies with immunity in a federal proceeding, that testimony cannot be used against them in a state prosecution.

That makes good sense. If a person’s testimony could be used against them at a different jurisdictional level, they would still be able to invoke the Fifth Amendment and refuse to answer questions. It can, however, complicate matters when prosecutors at one level try to prosecute a person who received immunity at a different level. One thing that trips up prosecutors in these situations is the requirement that to prosecute someone who has been given immunity they must establish that their evidence is independent of any immunized testimony. That can get tricky.

William Ortman does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.