Lawyers should always consider every possible evidentiary protection their clients might legitimately assert. To put it in basic terms, the ancient attorney-client privilege has the advantage of providing absolute protection from discovery – but is very fragile, and therefore easily lost (by the presence of third parties or through disclosure to third parties). The more recently created work product doctrine does not offer such absolute protection (except for opinions) – but is robust, and thus normally can be safely be shared with friendly third parties without risking a waiver.
In Champion Painting Specialty Services Corp. v. Delaware River Port Authority , Civ. No. 21-10146 (NLH/SAK), 2022 U.S. Dist. LEXIS 74626 (D.N.J. Apr. 25, 2022), the court emphasized both the societal purpose and the strength of the attorney-client privilege. The court first noted that the privilege's purpose is to "encourage full and frank communication between attorneys and their clients and thereby promote broader public interests in the observance of law and administration of justice." Id. at *7. The court then cited a Third Circuit case in emphasizing the privilege's absolute protection: "relevance is not the standard for determining whether or not evidence should be protected from disclosure as privileged, and that remains the case even if one might conclude the facts to be disclosed are vital, highly probative, directly relevant or even go to the heart of an issue" (quoting Rhone-Poulenc Rorer Inc. v. Home Indemnity Co., 32 F.3d 851, 864 (3d Cir. 1994). Id. at *8.
Because it was not relevant, the court did not go on to emphasize the "bad news" – that privilege protection is incredibly fragile. Lawyers must consider that risk when seeking the privilege's absolute protection.