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.