Most attorneys are aware that the attorney-client privilege is something to be protected with vigilance at all times. For that reason, attorneys may avoid disclosing any client communications to third parties to guard against any suggestion of waiver. However, there are many circumstances where a client might find himself aligned with another party to a litigation or transaction, and thus might find it beneficial to engage in the type of strategic discussions that are usually reserved for a client and her attorney.

For those situations, the joint defense or common interest privilege comes into play. However, while many attorneys may be vaguely aware of those doctrines or might presume that they will automatically apply under certain circumstances, there can be significant variation in the scope of the privileges depending on the jurisdictions.

In California, for example, the common interest doctrine acts as exception to the waiver of the attorney-client privilege. It applies where "parties have in common an interest in securing legal advice related to the same matter" and the communications at issue are "made to advance their shared interest in securing legal advice on that common matter," as in Seahaus La Jolla Owners Association v. Superior Court, 224 Cal. App. 4th 754, 770, 169 Cal. Rptr. 3d 390, 402 (2014) (citation omitted).

Other jurisdictions vary over whether they even recognize a joint defense or common interest privilege, as well as to what extent such a privilege applies. To avoid ambiguity, attorneys may choose to pursue a formal written agreement on behalf of their clients, although such an agreement does not always need to be in writing to be enforceable.

An initial challenge can sometimes be trying to distinguish between the two doctrines, as some courts use the terms "joint defense" and "common interest" almost interchangeably. However, the distinction can be very important in those jurisdictions that may narrowly define the joint defense privilege as applying only in the context of pending litigation, whereas the common interest doctrine may apply in much broader circumstances.

Thus, in order to ensure that communications will be protected, it is helpful for attorneys to understand the scope of the privileges and the factors that may undermine their application.  Here are some tips to consider.

The Joint Defense Privilege

In litigation, co-defendants often share a common interest in defeating the plaintiff's claims. That is certainly true where the co-defendants are not looking to blame one another. Even where defendants may assert claims against one another, they may be united in other areas of strategy. In that context, although communications among the defendants are likely not protected in the event of a subsequent dispute between them, the communications could be protected from discovery by the plaintiff if the defendants share a joint defense.

Although it may be framed as a "privilege" for ease of reference, joint defense does not typically function as a standalone privilege but instead is usually considered an exception to the rule on waiver of the attorney-client privilege. More specifically, while the disclosure of privileged information to a third party may waive the privilege, parties to a joint defense agreement can generally preserve the privilege while sharing confidential information between them.

To maintain the privilege in sharing communications with others, a party typically is required to prove three elements: that the communications were made pursuant to a joint defense, that the communications were made to further the goals of that joint defense, and that the privilege was not otherwise waived (i.e., the joint defenders are not sharing the communications beyond their limited group).

Define the Relationship

Although it may not be necessary to document the existence of a joint defense arrangement, many attorneys choose to do so in order to clarify the scope and duration of the relationship. In reviewing the validity of a joint defense agreement, courts generally focus on whether the interests of the co-parties are truly aligned.

For example, courts have found that simply sharing a desire to win a lawsuit is not enough to define a joint defense (or a common interest). By articulating the shared legal interest, practitioners may be able to increase the likelihood that their clients' shared confidences will be protected.

Consider Conflicts of Interest

The fact that parties are represented by separate counsel can create the perception that there are some issues on which the parties' interests do not align. When potentially differing interests evolve into actual differences in approach, strategy or resolution, the very predicate of the joint defense can be jeopardized.

To address such circumstances, a joint defense agreement can address exactly what happens if one party decides to terminate it or abandon the agreement (for example, if one of the parties becomes adverse to another). This can include addressing any duties to nonclients who are parties to the joint defense agreement.  Many joint defense agreements will specify that the joint defense relationship shall not serve as a basis to try to disqualify another counsel in the future, nor does it support an attorney-client relationship between one party and another party's lawyer.

Common Interest Agreements

Of course, not every matter in which parties want to exchange information with each other involves litigation. To address this possibility, many courts have extended the principles of the joint defense privilege to the nonlitigation context for those parties that share common interests.

The concepts and predicates for an enforceable common interest agreement are often similar to those of the joint defense agreement. Because the existence of common interests is not as obvious as in the litigation context, clients and attorneys may choose to take special steps to document the inception, duration, scope, boundaries and termination of any common interest in an agreement. Provisions confirming the attorneys' duties, or lack thereof, are again helpful to avoid needless future disputes including costly motions to disqualify.

Collaboration among parties with aligned interests can be often be extremely beneficial to both parties while potentially reducing expense. By understanding the joint defense and common interest privileges, attorneys can avoid incurring unnecessary risk when working with other parties.

Shari L. Klevens is a partner at Dentons US and serves on the firm's US Board of Directors. She represents and advises lawyers and insurers on complex claims, is co-chair of Dentons' global insurance sector team, and is co-author of "California Legal Malpractice Law" (2014).

Alanna Clair is a partner at the firm and focuses on professional liability defense. Klevens and Clair are co-authors of "The Lawyer's Handbook: Ethics Compliance and Claim Avoidance."