A common reason for a witness to be unavailable is that the witness is claiming a Fifth Amendment privilege against self incrimination.

Called before the Senate Internal Security subcommittee, she invoked her Fifth Amendment privilege against involuntary self-incrimination when asked if she was a member.

All nine Justices agreed that the woman, Amanda Mitchell, retained the right to invoke her Fifth Amendment privilege.

Compliance confronted Byers with "substantial hazards of self-incrimination" in violation of his Fifth Amendment privilege.

The Government believed that petitioners were likely to assert their Fifth Amendment privilege.

"It should be self-evident that a witness's mere claim of innocence does not preclude invoking the fundamental Fifth Amendment privilege," the appeal continued.

They appealed, arguing that the instructions to the jury violated their 5th Amendment privilege to not incriminate themselves.

However, it was leaked that he had invoked his Fifth Amendment privilege to avoid testifying before a grand jury some years prior.

Ms. Lewinsky cannot be forced to testify in a criminal case against Mr. Clinton: she can claim her Fifth Amendment privilege.

Instead those Iran-contra spark plugs went before a special Senate-House committee and invoked their Fifth Amendment privilege against self-incrimination.