National Association of Attorneys General
The Common Interest Doctrine�s Development and Expansion
The common interest rule or common interest doctrine is an evidentiary privilege that serves to limit the discoverability of certain materials. Many courts describe the common interest rule as an exception to the waiver of the attorney-client privilege. The general rule is that the attorney-client privilege is waived for any material that is disclosed to a third party. The common interest doctrine allows disclosures to a third party to remain privileged, so long as that party has a common legal interest. The purpose of the attorney-client privilege is to encourage the free flow of information to produce the most effective legal advice possible. Courts reasoned that permitting the exchange of communications among defendants with a common defense strategy promotes this same goal; therefore a privilege should exist to protect such communications.
The common interest doctrine developed from the joint defense privilege in criminal cases, was first recognized in 1871. The rule in its initial formulation was limited in its application, stating that a criminal defendant did not waive the attorney-client privilege by disclosing confidential information to co-defendants while in the presence of counsel. The privilege articulated in the Chahoon case was originally very limited in scope, only applying to communications between codefendants and counsel in criminal cases. The privilege was, however, broad enough to apply when the defendants have separate attorneys. The general rule was that a disclosure of material to a third party waives any privilege; however the joint defense doctrine developed as an exception to waiver.
Courts expanded the scope of the joint defense privilege as they were faced with different variations on the original, limited situations in which it applied. Eventually the legal system was presented with cases in which co-defendants in civil actions were attempting to assert the joint defense doctrine. Courts recognized application of this privilege to the civil arena, stating that the same underlying reasons for attorney-client privilege apply to parties in civil cases, so civil defendants should be afforded the privilege as well. Courts first recognized the more expansive common interest doctrine when they were faced with determining whether the joint defense doctrine applied in even more situations. Cases presented questions as to whether the privilege covered communications that civil co-plaintiffs or even parties not involved in the suit, shared while in the presence of counsel in furtherance of a joint strategy. The U.S. District Court for the Central District of California, for instance, recognized an expanded definition of the privilege, which covers plaintiffs as well. The Court, in the Sedalcek case, reasoned that the extension of the rule was done to achieve fairness, because otherwise cooperating defendants would be better situated than their plaintiff counterparts.
The more expansive statement of the doctrine extended the privilege to any allied party in a civil action, whether plaintiff or defendant. The common interest doctrine operates in the same way as the joint defense privilege and provides an exception to the general rule that a client waives the attorney-client privilege by communicating previously privileged information to a third party. Such an application of the doctrine is more expansive and permits represented parties who share a common legal interest to exchange otherwise privileged information in a confidential manner for the purpose of obtaining legal advice without waiving the attorney-client privilege.
Courts applying the common interest doctrine generally require that the party invoking it prove the following: (1) that an underlying privilege such as the attorney-client privilege protects the communication; (2) that the parties disclosed the communication at a time when they shared a common interest; (3) that the parties shared the communication in furtherance of that common interest; and (4) that the parties have not waived the privilege. The common interest doctrine has been expanded over time, in several ways. Some courts have allowed the doctrine to apply to the work product privilege for attorneys. Courts extended the rule to cover work product because it furthers the fundamental goals of the attorney-client privilege. Parties should be able to share otherwise privileged information freely and without fear of it being used against them later.  Therefore, in some circumstances the work product privilege, not just the attorney-client, can be the underlying privilege for application of the common interest doctrine. Moreover, the common interest doctrine has been expanded by some courts to cover communications that do not occur in the presence of counsel. This is a minority position, but serves to illustrate the expansion of the rule.
Deliberative Process Privilege
The common interest doctrine has been extended in yet another direction by some courts, which have applied it in the context of the deliberative process privilege. The deliberative process privilege applies to government agencies and protects “internal communications consisting of advice, recommendations, opinions, and other materials reflecting deliberative or policy-making processes,” but not “purely factual or investigative reports.” The seminal Modesto case dealt with a challenge to the decision of the National Marine Fisheries Service (NMFS), listing a type of Pacific salmon as endangered pursuant to the Endangered Species Act. The main issue in the case concerned the departure from previous decisions by the NMFS. The new decision separated the steelhead and rainbow trout, listing each individually, which was not consistent with previous decisions. The plaintiffs sought information that was shared between agencies containing deliberations about the decision. The line of reasoning used to extend the rule to cover the deliberative process was similar to that which was used to extend the rule to cover the work product privilege:
The deliberations served the common governmental purpose of resolving disagreements and formulating a mutually agreeable policy to comply with the law. The agencies were engaged in a common effort and sought the advice of counsel about fulfilling their statutory mission… Here, although the documents for which the attorney-client privilege is asserted were shared between multiple agencies, those agencies shared the common goal of reaching a mutually acceptable policy decision that would withstand legal challenge. Accordingly, the common interest doctrine operates to protect these documents from disclosure.
This is a good example of why many courts see the common interest doctrine as an exception to the waiver of attorney-client privilege. This court held that the government did not waive its privilege because it shared information with a party who had a common interest. The court held that all agencies of the federal government were not to be treated as one agency for the purpose of attorney client privilege, but applied the common interest rule to the deliberative process, making certain materials privileged.
One difference between the application of the common interest rule to the attorney-client privilege and the deliberative process privilege is that the deliberative process privilege is qualified, not absolute. Thus, as one court held, “[e]ven once the Court has found that the privilege applies, the documents will still be disclosed if the requesting party’s need for the documents outweighs the agency’s interest in holding them. Any analysis of whether certain material is discoverable must consider not only the circumstance under which it was shared to further a common goal, but also the underlying justification for protecting the information. As in all assertions of deliberative process privilege, the value of free communication among decision-makers must outweigh the public’s reasons for wanting the information disclosed--otherwise the material will be discoverable.
Another way that application of the common interest rule has changed over time is the requirement of confidentiality agreements. Early cases suggested that a confidentiality agreement among the parties was a necessity, or parties could not invoke the common interest doctrine. More recently, courts that have faced this issue have held that if a communication is not first privileged as between a client and his or her attorney, neither the common interest doctrine nor a confidentiality agreement can create a privilege. This is a logical extension of the principle that a formality cannot substitute for the circumstances that establish a genuine attorney-client communication; a confidentiality agreement alone will not create a privilege. The court in Niagara spoke to earlier courts’ analyses, which were predicated on pre-existing requirements of confidentiality agreements, holding that such agreements can be inferred from the actions of the parties. Such agreements may indicate the intent of the parties to ensure that their communications remain confidential. This helps the party seeking to apply the common interest doctrine meet the burden of proof by manifesting the parties’ joint intent that shared information remains confidential. Where the Niagara line of reasoning is adopted, it means that these agreements are no longer required, but they can serve as proof of the intent of the parties attempting to assert the common interest doctrine.
In summary, the common interest rule has been expanded significantly over time by the courts. The rule came from the idea of allowing criminal co-defendants to share confidential information without waiving the attorney-client privilege. The rule eventually spread to the civil arena, where it was eventually applied to any allied parties, whether plaintiff or defendant. The rule has been expanded in some jurisdictions to include the work product and deliberative process privileges as well, allowing more protection for attorneys and the government.
 Bill Brown served as Ohio Attorney General from 1971-1983 after receiving his law degree from Ohio Northern University. The school later established a NAAG scholarship in his honor. Stephen Nevius is a law student from Ohio Northern Petit College of Law.
John Doe, 902 F.2d 244, 248 (4th Cir. 1990) ,Niagara Mohawk Power Corp. v. Megan-Racine Assocs., Inc. 189 B.R. 562, 571 (Bankr. N.D.N.Y. 1995).
 See Chahoon v. Commonwealth, 62 Va. 822 (1871).
 Id. at 841-42.
 Id. at 823.
 See United States v. Schwimmer, 892 F.2d 237, 243 (2d Cir. 1989).
 See Schmitt v. Emery, 2 N.W.2d 413 (Minn. 1942)(overruled on other grounds, 215 Minn. 288(Minn.1943; Niagara Mohawk at 562.
 In re Grand Jury Subpoenas, 406 F.Supp. 381 (S.D.N.Y. 1975); Visual Scene, Inc. v. Pilkington Bros., 508 So. 2d 437, 440-41 (Fla. Dist. Ct. App. 1987).
 Sedalcek v. Morgan Whitney Trading Group, Inc., 795 F. Supp. 329, 330 (C.D. Cal. 1992); see also Hanover Ins. Co. v. Rapo & Jepsen Ins. Servs., 449 Mass. 609.
 Id at 331.
 Matter of Grand Jury Subpoenas; In re LTV Sec. Litig., 89 F.R.D. 595, 604 (N.D. Tex. 1981).
 In re Grand Jury Subpoenas at 385; Niagara Mohawk, 189 B.R. at 571; See. An Uncertain Privilege, 15 B.U. Pub. Int. L.J. 49.
John Doe at 249.
 Id. at 249.
 See Matter of Grand Jury Subpoena; Hunydee v. United States, 355 F.2d 183 (9th Cir.1965).
 See Modesto Irrigation Dist. v. Gutierrez, 2007 U.S. Dist. LEXIS 21949 (E.D. Cal. Mar. 8, 2007).
Brockway v. Department of Air Force, 518 F.2d 1184, 1190.
> 202007 LEXIS 21949, 12.
 Id. at 54-55.
 Id. at 54-55; See F.T.C. v. Warner Commc'ns Inc., 742 F.2d 1156, 1161 (9th Cir.1984).
Niagara Mohawk, 189 B.R. at 571.
 Minebea Co., Ltd. v. Papst, 228 F.R.D. 13, 15 (D.D.C. 2005) .
 See Chahoon.
 See Schmitt; Niagara.
 John Doe at 249.