When can a firm represent a client with interests materially adverse to a client of a former lawyer?

A law firm may represent a client with interests materially adverse to a client of a former lawyer primarily when the matters are not the same or substantially related, especially if the remaining lawyer possesses protected information from the former client. This principle stems from the concern about conflicts of interest and the obligations that lawyers have to their former clients.

When a lawyer leaves a firm, certain confidences and secrets regarding the former client's case must be protected. If the new representation involves a matter that is substantially related to the previous representation and the remaining lawyer has access to protected information, it creates a significant risk of breaching the duty of confidentiality owed to the former client.

The rules also allow the new representation to proceed when the matters are unrelated, as there is no overlap that would jeopardize confidentiality or create a conflict of interest. Additionally, client consent can sometimes resolve potential ethical conflicts, but the primary conditions involve the relationship between the matters in question and the potential access to confidential information. Thus, it is essential to evaluate whether the matters involved are substantially related and whether any protected information from the former client is relevant to the new representation.