The attorney-client privilege provides absolute but fragile protection. In contrast, work product doctrine protection can be overcome — but offers more robust safety than the privilege. This distinction affects the impact of third parties' participation, and disclosure of protected communications or documents to third parties.

In Wichansky v. Zowine, No. CV-13-01208-PHX-DGC, 2015 U.S. Dist. LEXIS 132711 (D. Ariz. Sept. 29, 2015), the court dealt with plaintiff's communications with his lawyer — in the plaintiff's father-in-law's presence. The court found that the father-in-law's participation rendered the privilege unavailable — holding that the father-in-law "was not necessary to Plaintiff's communications with his counsel and [therefore] does not fall within the privilege." Id. at *6. In addressing the work product doctrine, the court applied the universal rule that "unlike the more sensitive attorney-client privilege, waiver of work product protection does not occur simply because a document is shared with a third person." Id. at *10. Because the father-in-law's "interests are aligned with Plaintiff's," disclosing work product to the father-in-law did not waive that separate protection. Id. at *11. In fact, the court concluded that the plaintiff's father-in-law could himself prepare protected work product under Fed. R. Civ. P. Rule 26(b)(3)(A) — which can cover documents prepared in anticipation of litigation "for" a party (such as the plaintiff). Id. at *7.

The attorney-client privilege and the work product doctrine apply in dramatically different ways in the context of friendly third parties — who are generally outside privilege protection but inside work product protection, and who, even themselves, can create protected work product. Corporate lawyers should remember these rules when considering their corporate clients' friendly third parties such as accountants, consultants, or other agents.