Clients (or their lawyers) clearly waive the attorney-client privilege by revealing the substance of their privileged conversations. Does a client ever waive the privilege by testifying that he or she did not speak with a lawyer about a subject?
In United States v. Pinho, Crim. No. 02-814, 2003 U.S. Dist. LEXIS 12244 (E.D. Pa. July 8, 2003), Pinho testified at her obstruction of justice trial that she had not spoken with her lawyer about whether a subpoena had been issued, or whether documents might be submitted to a grand jury. After the jury deadlocked, the government prepared to retry Pinho. The court found that Pinho could have refused to answer questions about whether she had spoken with her lawyer about a particular subject, and that her denial about discussions with her lawyer waived the privilege. The government could therefore question her lawyer about whether there had been such discussions.
Civil litigants should never assume that privilege holdings in criminal cases apply with equal force to civil cases, and the Pinho court undoubtedly suspected that Pinho lied when she denied discussions with her lawyer. Still, civil litigators should remember this peculiar rule, and generally instruct their clients not to answer any questions about whether they did—or did not—discuss particular subjects with their lawyers.