History suggests that the attorney-client privilege is the oldest of the evidentiary privileges. It probably arose at common law during the 1500's, concurrent with the right to trial by jury. Judges initially viewed the privilege as a vindication of "the oath and the honor of the attorney." However, during the late 1700's, courts began to assert that the privilege's purpose was to encourage clients to make full disclosure to their counsel, by "providing subjectively for the client's freedom of apprehension." In 1871, the Virginia Supreme Court5 stated that "[i]f the privilege did not exist at all, every one would be thrown upon his own legal resources; deprived of all professional assistance, a man would not venture to consult any skillful person, or would only dare to tell his counsel half his case." Today, courts continue to state that the benefits of full disclosure justify the privilege, and frequently assert that without such full disclosure an attorney may not be able to adequately advise his client.
Thomas C. Dawson Jr., John T. Tucker III & Kevin J. Whyte,
The Attorney-Client Privilege,
U. Rich. L. Rev.
Available at: http://scholarship.richmond.edu/lawreview/vol19/iss3/9