Consider the following scenario: Witness (not defendant) asked to testify at a civil case at a state court. Witness takes the fifth out of nowhere, that is at a completely unexpected place in testimony where it appears there is nothing even remotely connected to the case could possibly result in a fifth amendment, with the obvious conclusion that the fifth amendment is being taken for something the court doesn't even know about yet. The state grants immunity from prosecution to get testimony.

But the crime covered by the fifth amendment is a federal crime and the state granted immunity.

Is the fifth amendment protection broken, or did the state just bind the federal government to not prosecute something?

I am aware that the state usually doesn't grant blanket immunity (all possible charges revealed by testimony rather than a list beforehand), but if they are intent on compelling testimony and they don't know what the crime being covered is, and they have no way to find out ...

Perhaps there's a way to invoke the fifth in such a manner as to get immunity from the right court, but there is no documentation readily available on the matter. But in that case we have to consider what happens of the federal court refuses to grant immunity. Hint: if the state is a party to a civil case they're likely to grant immunity, but why would a federal judge care?

2 Answers 2


There are two kinds of immunity: formal and informal. They have different consequences.

Informal immunity is an agreement between the defendant and the prosecutor's office, after which the defendant voluntarily gives testimony. Because the defendant is voluntarily giving testimony, they're waiving their Fifth Amendment privilege. The prosecutor will be held to their agreement, and it's possible that other prosecutors under the same sovereign are held to the agreement, but the agreement doesn't bind other governments. Because your statement under informal immunity was voluntary and you waived your Fifth Amendment privilege, other governments can use those statements against you. There might be an exception to that rule if the two governments were working together to trick you, but if they were working independently there's no issue with the second government using the statements.

Formal immunity is when a court orders you to testify notwithstanding Fifth Amendment privilege. This does bind other governments, but not as broadly as you seem to think. The minimum level of immunity for compelled testimony is called "use and derivative use immunity:" the government can't use the compelled testimony or any evidence derived from it against you. It does not prevent the government from prosecuting you with evidence they got independently. Informal immunity is more flexible (since it's an agreement), but informal immunity also often takes the form of "we won't use what you say against you" instead of "we won't prosecute you for X."

Some states require transactional immunity to compel testimony (that's where you can't be prosecuted for any crime you admit to during the questioning as long as the admission was actually relevant to the question). However, this goes beyond the requirements of the Fifth Amendment, so it's not binding on other governments. Other governments are only bound (under the federal constitution) by use and derivative use immunity. See Murphy v. Waterfront Commission for discussion of the federal government having to comply with use and derivative use immunity principles if a state court compels testimony.

  • So there is a problem with this answer; unfortunately the problem exists within the practice of law enforcement rather than the text of the answer: en.wikipedia.org/wiki/Parallel_construction
    – Joshua
    May 6, 2018 at 18:41
  • Parts of this answer are wrong. A court does not order immunity for a witness, only a prosecutor generally has that authority. Additionally most of this answer is misleading or wrong. See Murphy v. Waterfront Comm'n, 378 U.S. 52 (1964)
    – Viktor
    May 6, 2018 at 22:28
  • @Viktor A prosecutor requests immunity; however, a prosecutor cannot compel you to talk. Courts have that power, and while they exercise it on request of the prosecutor it's the court's power. And I have no idea what you mean by citing Murphy; if you think that all immunity is binding on all levels of government that's completely wrong (informal immunity is not binding on other governments), and if you mean formal immunity is binding you'll notice that I actually cited Murphy in my answer. If you're going to try to point me to a case I cited, please be more specific in what you mean.
    – cpast
    May 6, 2018 at 22:40
  • 1
    For references: A court, not a prosecutor, actually issues the order to talk in federal court. Informal immunity exists and does not bind other governments. Same deal at the state level. Murphy gives the "use and derivative use" rule. So @Viktor exactly which part of the answer is wrong, and based on what?
    – cpast
    May 6, 2018 at 22:47
  • Informal immunity is not immunity. In the context of the question it is misleading. At least that is my opinion.
    – Viktor
    May 6, 2018 at 22:50

If the state granted immunity in a civil case, then it is binding. The Supreme Court has previously held that states may issue use and derivative use immunity testimony that is binding upon the federal and state government. See Murphy v. Waterfront Comm'n, 378 U.S. 52 (1964).

Thus generally the rules of use and derivative use immunity apply to any testimony. These rules prohibit prosecution using any evidence obtained from or as a result of the testimony for which immunity was granted. For a prosecution to proceed, the sovereign prosecuting must establish that all the evidence was obtained independently of the testimony in question.

In a small number of states, the state must grant transactional immunity before compelling a witness to testify on a manner that could subject them to prosecution. What this means is the state could not bring any prosecution against any facts revealed in the testimony. To my knowledge, it has not been decided if that is binding on the federal government. Based on the reasoning behind the holding in Murphy, I would suspect that a grant of transactional immunity would not be binding on the federal government, but the rules of use and derivative use would obviously apply.

  • This answer does not discuss the common case of informal immunity and so is leaving out a major part of the picture. Informal immunity does not bind any other government.
    – cpast
    May 6, 2018 at 22:49

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