Okay, so last week I laid out a fairly typical conversation in which a witness is reluctant for the some of the more common reasons that witnesses become reluctant to testify. So what is Prosecutor going to do now?
Theory: First, let's look at some of the theory behind the 5th Amendment and testimony in general. The clause which pertains to all this is "No person . . . shall be compelled in any criminal case to be a witness against himself." This is an affirmation of the adversarial judicial system we lifted off the British and a rejection of the inquisitorial system, under which the defendant was traditionally required to confess. We have carried this beyond star chambers and ecclesiastical courts; we extend it to any time a law enforcement agent has someone in a situation where a reasonable person would feel free to leave.
On the other hand, a person cannot invoke the 5th in order to avoid breaking the law. Specifically, a witness cannot invoke the 5th in order to keep from committing perjury. She also cannot take the 5th because she does not want to testify or any reason except that what she would say would incriminate her. Any attorney appointed to or hired by her would be unable to advise her to take the 5th except in a case where it would incriminate her because were he to do otherwise he would be in breach of his ethical requirement, as an officer of the court, not to perpetrate a fraud on the court.
Reality: An extra-constitutional invocation of the 5th Amendment looks exactly the same as a valid invocation of the 5th Amendment. If the witness is smart enough to figure this out on her own, or even just bull-headed ("I seen it on TV. I don't have to testify no matter what.") she can game the system.
Possible Prosecutor Reactions: Going back to the last post, Jane has just told Prosecutor that she is going to invoke the 5th amendment. What can poor helpless Prosecutor do?
1) The Lecture - "YOU. CANNOT. TAKE. THE. 5TH. JUST. BECAUSE. YOU DO. NOT. WANT. TO. TESTIFY. That man beat you. I won't drop charges when a man chokes and beats someone. I'm going to call you and you should tell the truth."
Any number of times that will be all that is necessary. Often, shortly after she has returned and told boyfriend the prosecutor's going to call her, even though she doesn't want to testify, he'll send Defense Counsel over to actually finalize the plea. However, for our example we'll assume that doesn't happen and she does take the 5th when called.
2) Try the case without her. This can be difficult, although not as hard as it used to be. It has been my experience that a lot of deputies/officers have started carrying inexpensive digital cameras and taking pictures of domestics - not all of them, but it seems to be spreading. Prosecutor can show the picture, put forth any statement by Defendant, and maybe even play the 911 tape of Jane calling for help. If Jane testifies for Defendant the prosecutor even has built in, and fairly devastating impeachment evidence from her statement to the police that night.
However, in the facts I put forth Defendant made no statement and, unless he knew there was going to be trouble ahead of time, Prosecutor probably won't have the 911 tape. So, that leaves option 3.
3) Give Jane use immunity (or actually what Virginia cases call "use derivative immunity"). Ask the judge to instruct Jane that, "Use immunity means that nothing that you say today and no evidence that is developed from what you say can be used in a trial against you. There is only one exception to this. Immunity does not protect you if you commit perjury. Once you have been granted immunity you cannot invoke your 5th Amendment right and you must now testify to the best of your knowledge and ability." Then require her to testify.
This is the most likely outcome. Why use "use immunity?" Lets assume Jane tells the new story to the judge and remember she made inculpatory statements to the prosecutor. She has either made a false report to an officer or committed perjury. If the new story is a true then the report to the police on the night of the incident is a lie. This is a "Making a False Statement" misdemeanor. If the new story is a lie and the report to the police is true then she has committed perjury, a felony. If Prosecutor has given her transactional immunity he's going to face an argument that she can't be prosecuted for her actions on that night.1 This paints him into the a corner which requires him to charge Jane with the felony.
Or, if you want to view this from the perspective of a totally unsympathetic, hard core prosecutor, it gives Prosecutor the option of indicting her on both charges and letting a jury figure out which one it will convict her on.
1 I say "an argument" because the counter argument would be that she was not a "transactor" but a victim in the thing about which she is testifying. The report to the police is collateral and post-event. And before anyone screams at me, no, I have not looked at case law relevant to this argument - it just hit me as I was typing.