Formal Opinion 136.
(1968)
Claim Against Former Client

An inquiry has been directed to the propriety of representing a guardian and his ward in one legal action and then representing the guardian in a later action brought against him by the ward.

Canons 6 and 37 make it unethical to accept employment with a client against a former client where such employment would require the attorney to contend for that which his duty to the former client would require him to oppose, and as to any matter adversely affecting confidences reposed in him by the former client. Washington Ethics Opinion 45 (1956) suggests that the use of any information gained in representing the former client, confidential or otherwise, makes the later representation improper.

Representation of the guardian and the ward in the prior action, during which information would undoubtedly be gained from both, makes representation of the guardian against the ward in a later action improper.