United States v. Mezzanatto, 513 U.S. 196 (1995) (U.S. Supreme Court)
United States v. Mezzanatto is a landmark Supreme Court decision at the intersection of evidence law and plea bargaining practice.
May a criminal defendant waive the protections of Federal Rule of Evidence 410 and Federal Rule of Criminal Procedure 11(e)(6) so that statements made during plea discussions can be used to impeach the defendant's testimony at trial?
Personal rights and evidentiary protections are presumptively waivable absent an affirmative indication to the contrary in the governing statute or rule. Neither Federal Rule of Evidence 410 nor Federal Rule of Criminal Procedure 11(e)(6) contains an anti-waiver provision or otherwise demonstrates congressional or rulemaking intent to bar defendants from agreeing to impeachment use of plea-discussion statements. Consequently, a defendant may knowingly and voluntarily waive these protections and permit impeachment use of such statements.
Yes. A defendant may waive the protections of Rule 410 and Rule 11(e)(6). A prosecutor may use plea-discussion statements to impeach a testifying defendant who offers testimony inconsistent with those statements, if the defendant entered a knowing and voluntary waiver allowing such use.
Mezzanatto is foundational to modern federal proffer practice. After this decision, prosecutors routinely require "Mezzanatto waivers" in proffer letters, at minimum permitting impeachment use if the defendant later testifies inconsistently. The case reframes Rule 410/Rule 11 protections as personal, waivable rights rather than categorical exclusions, thereby altering defense strategy when counseling clients about cooperation. While Mezzanatto expressly addresses impeachment use, many courts have grappled with the scope of waivers and, in some jurisdictions, have enforced broader clauses permitting rebuttal or even case-in-chief use if clearly agreed to. For law students, the case illustrates how evidentiary rules interact with bargaining dynamics, the doctrine of waiver, and the tension between truth-seeking and policy-based exclusions.