Which rule governs conflicts with former clients?

• A. Model Rule 1.9.
• B. Model Rule 1.8.
• C. Model Rule 1.6.
• D. Model Rule 1.2.

Answer: (A)

Conflicts with former clients are governed by Model Rule 1.9. When you have represented a client in a matter, you may not later represent a new client in the same or a substantially related matter if that new client's interests are materially adverse to the former client, unless the former client provides informed consent in writing. The rule also protects confidential information obtained from the former client, prohibiting its use to the former client's disadvantage in the new matter, again with the written consent exception only for what is allowed by the rules. This framework exists to prevent a lawyer from exploiting prior insider knowledge or loyalties at the expense of someone the lawyer previously represented.

The other rules address different topics—confidentiality of information, the scope of representation, and dealings with current or prospective clients—so they don’t govern the specific situation of conflicts with a former client in the same or a substantially related matter.