Most courts recognize what is called the “joint defense” or “common interest” doctrine. That doctrine provides protection to communications among clients (or their lawyers) if the clients share an identical legal interest, and the communications are in furtherance of that interest. However, lawyers should remember that the common interest doctrine only serves to protect communications that are otherwise privileged, and does not create an independent source of protection.
The court in McNally Tunneling Corp. v. City of Evenston, ILL., No 00 C 6979, 2001 U.S. Dist. LEXIS 17164 (N.D. Ill. Oct. 18, 2001) articulated this principle. The court found that the common interest doctrine did not apply to a settlement agreement between a city and one of its agents reached in a construction dispute (because the settlement agreement obviously related to adversity between them), while the common interest doctrine protected later discussions between the city and the agent about a joint strategy for defending against the general contractor’s lawsuit against both of them. In undertaking this sophisticated analysis, the court explained that the common interest doctrine merely allows parties to avoid losing previously existing protections when they discuss privileged matters outside the attorney-client relationship, and does not represent an independent source of attorney-client privilege protection.
Lawyers should remember that the common interest doctrine is not a simple cure-all when parties with similar interests communicate, but instead requires careful analysis and application.