When multiple parties are involved in a matter, there may be situations when the parties' interests align or when the parties can mutually benefit from coordinating strategy or sharing information. For the attorneys representing those parties, the worry may be that communicating with other parties could risk waiver of otherwise applicable privileges and immunities, including the attorney-client and work-product privileges.

Fortunately, many state and federal courts have developed joint defense and common interest doctrines that can provide protection for communications among parties. However, the prerequisites and limits of these doctrines can vary dramatically from one jurisdiction to another, and in some jurisdictions there are severe limits on their application, if they exist at all.

California, for example, recognizes the common interest doctrine as a “nonwaiver doctrine” whereby disclosure is permitted between parties without waiver of privileges where communications would otherwise be protected by the attorney-client privilege or the attorney work-product doctrine and where the disclosure is necessary to accomplish the purpose for which the legal advice was sought. OXY Res. California v. Superior Court, 115 Cal. App. 4th 874, 889 (2004), as modified (Mar. 4, 2004); Citizens for Ceres v. Superior Court, 217 Cal. App. 4th 889, 914 (2013).