[Editor’s NoteThis post is part of a Just Security symposium on retired lieutenant general Michael Flynn’s legal jeopardy. Ready Alex’s earlier post, “Flynn’s Public Offer to Testify for Immunity Suggests He May Have Nothing to Say.” And stay tuned for more coverage specific to Flynn. See also our related coverage on the Logan Act, and Steve Vladeck on the Foreign Agents Registration Act and on treason.]

When the story broke on Thursday night that Michael Flynn was seeking immunity for his testimony, I wrote that the strategy of Flynn’s lawyer suggested that his client is not looking to offer up the goods on any other administration officials – either because he does not have them or is unwilling to provide them. Instead, I argued, it appears that Flynn and his lawyer were making a play for immunity from Congress, which would complicate any subsequent attempts to prosecute Flynn. On Friday, President Donald Trump tweeted that “Mike Flynn should ask for immunity in that this is a witch hunt…,” reinforcing the suspicion that the flipside of the president’s tweet was true: in seeking immunity from Congress, Flynn was looking for a political solution to his potential legal woes.

It is unsurprising that neither the Justice Department nor the Congressional committees have jumped to offer Flynn immunity, and it is unlikely that either will anytime soon. To understand why requires a brief explainer on immunity and how it figures into criminal and Congressional investigations.

Immunity can come in two different forms: “transactional immunity” and “use immunity.” Transactional immunity is a commitment from the government not to prosecute for specified charges, and is rarely offered. Why? Because such immunity exceeds what the government is required to give to achieve its investigative or law enforcement objectives. If what’s being sought is a person’s testimony, then what will be offered instead is the narrower use immunity, whereby a suspect or witness receives a commitment that nothing the witness says, nor anything derived from that testimony, will be used against that person in any future prosecution. A grant of use immunity eliminates a person’s Fifth Amendment privilege to refuse to answer questions. Since the person’s words cannot be used to incriminate that person in any future prosecution, the privilege no longer applies and the person can no longer refuse to answer questions if subpoenaed by a grand jury or Congress. Formally, a grant of use immunity is obtained by seeking an order from a judge.

In theory, then, a person who is compelled to testify pursuant to a grant of use immunity – either from Congress or the Justice Department – can still be prosecuted subsequently for alleged crimes that the person testifies about, so long as the prosecutors make no use or derivative use of the defendant’s testimony. And therein lies the rub. Derivative use has been broadly interpreted by the courts. It means that the prosecutors and investigators in the case cannot use the defendant’s compelled testimony for leads, but also cannot be influenced in any way – e.g., with regard to strategy or the focus of the investigation – by exposure to that testimony. These forms of derivative use are manageable: it simply requires all investigators and prosecutors working on the case to wall themselves off from any exposure to, or reporting on, the individual’s compelled testimony. 

In the Oliver North case, the Court of Appeals for the D.C. Circuit went further, and found that the prosecutor must also establish that no witnesses called by the prosecution (say, Mike Pence or Sally Yates) were tainted by their exposure to the defendant’s (Flynn’s) compelled testimony. Such taint could occur if the witness, consciously or unconsciously, modified his or her testimony, or “remembered” new information, as a result of hearing the defendant’s compelled testimony. In the North case, the prosecution was unable to establish that its witnesses were untainted by North’s compelled testimony before Congress, which was widely broadcast and reported upon, and therefore North’s conviction was reversed. To avoid this problem today, prosecutors will either try to get witness evidence “in the can,” before a suspect provides compelled testimony, so that the prosecution can show at trial that there was no taint, or they will adopt measures to screen witnesses before relying upon them to establish that they were not in fact tainted by exposure to statements compelled by the grant of use immunity.

What should now be clear is that when a person has testified pursuant to a grant of use immunity, it is extremely challenging to prosecute that person subsequently for matters that were the subject of the compelled testimony. For this reason, any federal prosecutor seeking a grant of use immunity must first get approval from an Assistant Attorney General, and the Attorney General of the United States must approve the subsequent prosecution of any person for a matter that was the subject of that person’s compelled testimony.

Accordingly, prosecutors will ordinarily seek an order of use immunity in only two tightly limited circumstances: either the prosecution has determined that under no circumstances will it prosecute the person it seeks to immunize, or it has reached a cooperation deal with the person. Under the first scenario, the prosecution might reach such a conclusion if it concluded, for example, that the person was a minor player in the criminality or it was not otherwise in the public interest to pursue prosecution. Regarding the second scenario, the prosecution will ordinarily only enter into a cooperation agreement, which may also include a guilty plea, if it first gets a preview of what information it might receive from the witness, and that’s where the so-called “proffer session” comes in. In a proffer session, the witness (who is usually also a suspect) agrees to give the prosecution a preview of the information he or she can offer in exchange for what might be called “use immunity lite”: the prosecution agrees that it will not make direct use of the witness’s proffer statement, but makes no promises with respect to derivative use. Why would the witness ever agree to this? Only if he or she believes that the government has strong evidence to prosecute and convict in any case, and therefore the witness (also a suspect) seeks to win concessions from the prosecution in exchange for his or her testimony. Because the government holds the cards in this scenario, the witness will agree to provide the preview of testimony, in a proffer session, with fewer protections.

So how does this all relate back to the Flynn case? It is impossible to believe that at this early stage we could be in the first scenario, that the Justice Department has already determined that Flynn will not be prosecuted under any circumstances (later in time, following more investigation, the Justice Department could still make that decision). Therefore, a grant of use immunity could only occur at this juncture under the second scenario: Flynn concludes that he faces such significant criminal exposure that it is in his best interest to seek a cooperation agreement with the prosecution, requiring him first to provide a “proffer” of his testimony so that the government can assess its value and veracity, which would then be followed by negotiations regarding the terms of a cooperation agreement. But if this was the road Flynn and his lawyer wanted to go down, they would not have made their request for immunity publicly. As I explained in my piece last week, if their goal was to obtain a deal from the prosecutors in exchange for cooperation, they would have proceeded in a way to win over the prosecutors, which would have meant approaching them quietly to preserve the integrity of the ongoing investigation.

For that reason, it seems that Flynn and his lawyer were seeking to appeal to one of the Congressional committees. But he won’t get immunity from them anytime soon either. The committees can grant use immunity to a witness only on a 2/3 vote of the committee, which means that some Democrats will have to go along. Further, the Justice Department can request that Congress delay the granting of any immunity so that it can advance its investigations without risk of taint. Both members of Congress and the Justice Department will recognize that in light of the court decision in Oliver North’s case, Flynn should be granted use immunity for his testimony only after the investigation into his conduct has substantially advanced. That will give investigators an opportunity both to assess his criminal exposure and to lock in the testimony of significant witnesses so that it could later be established that they were not tainted by exposure to compelled testimony.

In sum, if Flynn had the goods and were ready to offer them up, he could start talking to the Justice Department today. But that does not seem to be the case, and therefore it is likely that he will have to wait a long time for a grant of use immunity, which may never arrive.

Image: Kevin Hagen/Getty