The attorney-client privilege provides absolute protection, but is very fragile. Work product doctrine protection does not provide absolute protection (fact work product protection can be overcome), but is robust. Of course, documents and communications can be protected by both protections, one but not the other, or neither. Courts normally must assess each asserted protection's applicability, and (if the circumstances require it) each protection's separate waiver implications.
In Sure Fit Home Products, LLC v. Maytex Mills, Inc., No. 21 Civ. 2169 (LGS) (GWG), 2022 U.S. Dist. LEXIS 90833, at *1 (S.D.N.Y. May 20, 2022) (as corrected July 24, 2022), the Southern District of New York (Judge Gorenstein) explained that "[b]ecause we conclude that plaintiffs waived any claim to privilege over these documents . . . we need not reach the question of whether the exhibits would otherwise enjoy work product protection." The court's conclusion made sense in this case, because plaintiffs "produced [the protected documents] to their adversaries in two separate matters." Id. at *5. But different circumstances would have required a different analysis. If plaintiffs had disclosed the documents to friendly third parties rather than to adversaries, that disclosure might have waived the fragile privilege protection but not the more robust work product protection. In that situation, the court must assess possible work product protection, which might have survived the disclosure.
Lawyers should always consider both privilege and work product protection when analyzing withholding documents during discovery and when assessing waiver implications.