This Rule governed the practice of law in the District of Columbia from January 1, 1991, through January 31, 2007. As of February 1, 2007, the Amended Rules took effect.
(a) Except as stated in paragraph (b), a lawyer
shall not represent anyone in connection with a matter in which the
lawyer participated personally and substantially as an arbitrator, unless
all parties to the proceedings consent after disclosure.
(b) An arbitrator selected as a partisan of a party in a multimember arbitration panel is not prohibited from subsequently representing that party.
 This Rule extends the basic requirements of Rule 1.11 (a) to privately employed arbitrators. Paragraph (a) is substantially similar to Rule 1.11(a), except that it allows an arbitrator to represent someone in connection with a matter with which the lawyer was substantially involved while serving as an arbitrator if the parties to the arbitration consent. Paragraph (b) makes it clear that the prohibition set forth in paragraph (a) does not apply to partisan arbitrators serving on a multimember arbitration panel.