The unpredictable "at issue" waiver doctrine can strip away privilege protection without any disclosure of, or explicit reliance on, privileged communications. But state courts and even federal courts take widely varying approaches to this most dangerous type of implied waiver.

In Keller v. Arrieta, Civ. No. 20-259 KG/SCY, 2021 U.S. Dist. LEXIS 139536 (D.N.M. July 27, 2021), the federal district court applied New Mexico privilege law in rejecting an "at issue" waiver argument. The court stressed that "[w]hen determining whether a privileged matter is at issue, the New Mexico Court of Appeals has adopted a restrictive approach" – finding that "a party only waives her attorney-client privilege where she 'directly relies on attorney-client communications in order to advance a claim or defense.'" Id. at *10-11 (citation omitted). This reflects a very favorable standard for companies hoping to avoid an "at issue" waiver.

Given states' varying approaches to important waiver issues like the "at issue" doctrine, lawyers must always carefully consider choice of law issues when asserting a waiver or defending against a claim of waiver.