Use of Immunized Grand Jury Testimony for Impeachment Purposes
In Chapman v. California (386 US 18, 22 ), the Supreme Court set forth the standard to be applied when reviewing constitutional trial errors.
The Court declined to adopt a rule of automatic reversal for all such errors.
Some constitutional errors are so fundamental as to deny the defendant a fair trial without resort to a harmless error analysis.
In New Jersey v. Portash (440 US 450 ), the Supreme Court held that the threatened use of defendant's immunized Grand Jury testimony for impeachment purposes should the defendant take the stand was such an error, requiring reversal without resort to a harmless error analysis even though the defendant did not take the stand.
The Court equated use of such immunized testimony to the use of coerced confessions which are inadmissible for all purposes.