The Fifth Amendment (Amendment V) to the United States Constitution is part of the Bill of Rights and, among other things, protects individuals from being compelled to be witnesses against themselves in criminal cases. “Pleading the Fifth” is thus a colloquial term for invoking the right that allows witnesses to decline to answer questions where the answers might incriminate them, and generally without having to suffer a penalty for asserting the right. This evidentiary privilege ensures that defendants cannot be compelled to become witnesses at their own trials. If, however, they choose to testify, they are not entitled to the right during cross-examination, where questions are relevant to their testimony on direct examination. The Amendment requires that felonies be tried only upon indictment by a grand jury. Federal grand juries can force people to take the witness stand, but defendants in those proceedings have Fifth Amendment privileges until they choose to answer any question. To claim the privilege for failure to answer when being interviewed by police, the interviewee must have explicitly invoked the constitutional right when declining to answer questions.
The Amendment’s Double Jeopardy Clause provides the right to be tried only once in federal court for the same offense. The Amendment also has a Due Process Clause (similar to the one in the 14th Amendment) as well as an implied equal protection requirement (Bolling v. Sharpe, 1954). Finally, the Amendment requires that the power of eminent domain be coupled with “just compensation” for those whose property is taken.