In what circumstances does a lawyer remain disqualified from representing a client after switching firms?

A lawyer remains disqualified from representing a new client after switching firms primarily in situations where the former lawyer’s representation involved similar legal issues. This principle is rooted in the duty of loyalty that attorneys owe their former clients. When a lawyer has worked on a case related to a specific legal issue, there’s a potential risk that confidential information obtained during that representation could be inadvertently used in the new representation, which could harm the former client.

This is particularly significant in legal ethics because it ensures the protection of client confidences and the integrity of the legal profession. The disqualification is not solely about whether the cases are directly related; even tangential similarities in legal issues can create ethical concerns regarding confidentiality and loyalty.

In contrast, if a new client’s case is completely unrelated to the former client (as presented in another option), there generally would be no ethical concerns impacting the attorney’s ability to take on that representation. Knowledge of a case by another lawyer in the firm or the absence of prior direct contact with a client doesn’t automatically lead to disqualification either, as those circumstances don't directly reflect the lawyer's previous client commitments and the potential for conflicts arising from those past representations.