RULE 1.9 CONFLICT OF INTEREST: FORMER CLIENT
A lawyer who has formerly represented a client in a matter shall not thereafter:
Represent represent another person in the same matter in which that person's interests are materially adverse to the interests of the former client; or
Represent represent another person in a substantially related matter in which that person's interests are materially adverse to the interests of the former client unless the former client consents after consultation; or
Use use information relating to the representation to the disadvantage of the former client in the same or a substantially related matter except as Rule 1.6 these Rules would require or permit with respect to a client, or when the information has become generally known.
 After termination of a
client-lawyer lawyer-client relationship, a lawyer has certain continuing duties with respect to confidentiality and conflicts of interest and thus may not represent another client except in conformity with this Rule. The principles in Rule 1.7 determine whether the interests of the present and former client are adverse. Thus For example, a lawyer could not properly seek to rescind on behalf of a new client a contract drafted on behalf of the former client. So also a lawyer who has prosecuted an accused person could not properly represent the accused in a subsequent civil action against the government concerning the same transaction. Nor could a lawyer who has represented multiple clients in a matter represent one of the clients against the others in the same or a substantially related matter after a dispute arose among the clients in that matter, unless all affected clients give written consent. See Comment . Current and former government lawyers must comply with this Rule to the extent required by Rule 1.11.
The term "matter" is defined by Rule 1.7(e). The scope of a "matter" for purposes of this Rule may depend depends on the facts of a particular situation or transaction. The lawyer's involvement in a matter can be a question of degree. When a lawyer has been directly involved in a specific transaction, subsequent representation of other clients with materially adverse interests in that transaction clearly is prohibited. On the other hand, a lawyer who recurrently handled a type of problem for a former client is not precluded from later representing another client in a wholly factually distinct problem of that type even though the subsequent representation involves a position adverse to the prior client. Similar considerations can apply to the reassignment of military lawyers between defense and prosecution functions within the same military jurisdiction. The underlying question is whether the lawyer was so involved in the matter that the subsequent representation can be justly regarded as a changing of sides in the matter in question.
 Matters are "substantially related" for purposes of this Rule if they involve the same transaction or legal dispute or if there otherwise is a substantial risk that confidential factual information as would normally have been obtained in the prior representation would materially advance the client's position in the subsequent matter. For example, a lawyer who has represented a businessperson and learned extensive private financial information about that person may not then represent that person's spouse in seeking a divorce. Similarly, a lawyer who has previously represented a client in securing environmental permits to build a shopping center may not then represent neighbors seeking to oppose rezoning of the property on the basis of environmental considerations. However, the lawyer would not be precluded, on the grounds of substantial relationship, from defending a tenant of the completed shopping center in resisting eviction for nonpayment of rent. Information that has been disclosed to the public or to other parties adverse to the former client ordinarily will not be disqualifying. Information acquired in a prior representation may have been rendered obsolete by the passage of time, a circumstance that may be relevant in determining whether two representations are substantially related. In the case of an organizational client, general knowledge of the client's policies and practices ordinarily will not preclude a subsequent representation. On the other hand, knowledge of specific facts gained in a prior representation that are relevant to the matter in question ordinarily will preclude such a representation. A former client is not required to reveal the confidential information learned by the lawyer in order to establish a substantial risk that the lawyer has confidential information to use in the subsequent matter. A conclusion about the possession of such information may be based on the nature of the services the lawyer provided the former client and information that would in ordinary practice be learned by a lawyer providing such services.
Information Paragraph (c) provides that information acquired by the lawyer in the course of representing a client may not subsequently be used or revealed by the lawyer to the disadvantage of the client in the same or a substantially related matter except as Rule 1.6 would require or permit. Rule 1.6(h) would permit a However, the fact that a lawyer has once served a client does not preclude the lawyer to use from using generally known information about a former that client when later representing another client. The former client may consent to the lawyer's representation of an adverse party in a substantially related matter, but not to representation of an adverse party in the same matter. When consent is permitted, it is effective only after consultation with the client about the circumstances, including the lawyer's intended role in behalf of the new client. With regard to an opposing party's raising a question of conflict of interest, see Comment to Rule 1.7. With regard to disqualification of a firm with which a lawyer is associated, see Rule 1.10.
 The provisions of this Rule are for the protection of former clients and can be waived if the client gives written consent. With regard to the effectiveness of an advance waiver, see Comment  to Rule 1.7. With regard to disqualification of a firm with which a lawyer is or was formerly associated, see Rule 1.10.
Reference: Minutes of the Professional Conduct Subcommittee of the Attorney Standards Committee on 12/14/84, 02/08/85, 04/26/85, 08/23/85, 09/20/85 and 01/31/86; Minutes of the Joint Committee on Attorney Standards on 11/14/03, 02/27/04, 11/19/04, 06/14/05, 09/09/05.