Attorney-Client Privilege: Common Interest Doctrine (Federal)

by Thomas E. Spahn, McGuireWoods LLP with Practical Law Litigation

A Practice Note that examines how federal courts analyze the attorney-client privilege when parties share information under a common interest agreement, also known as a joint defense agreement. It explains that the common interest doctrine is an exception to the general rule of privilege waiver but is not a standalone doctrine. This Note discusses the requirement for an express agreement between parties and outlines the various factors courts scrutinize to determine if the doctrine applies, even when an agreement exists. These factors include the proximity to anticipated litigation, the degree of commonality in the participants' legal interests, the involvement of counsel, and whether the shared communications further a joint legal strategy. It also addresses the rules concerning privilege waiver among participants, the consequences if participants later become adversaries, and potential conflicts of interest for counsel. Finally, this Note distinguishes common interest agreements from joint representations, where the same counsel represents multiple clients.