(a) Except as provided in paragraph (b), a lawyer shall not represent a client if the representation involves a concurrent conflict of interest. A concurrent conflict of interest exists if:
(1) the representation of one client will be directly adverse to another client; or
(2) there is a significant risk that the representation of one or more clients will be materially limited by the lawyer's responsibilities to another client, a former client or a third person or by a personal interest of the lawyer.
(b) Notwithstanding the existence of a concurrent conflict of interest under paragraph (a), a lawyer may represent a client if:
(1) the lawyer reasonably believes that the lawyer will be able to provide competent and diligent representation to each affected client;
(2) the representation is not prohibited by law;
(3) the representation does not involve the assertion of a claim by one client against another client represented by the lawyer in the same litigation or other proceeding before a tribunal; and
(4) each affected client gives informed consent, confirmed in writing.
NEW HAMPSHIRE COMMENT
The requirements that a lawyer maintain loyalty to a client and protect the client's confidences are fundamental. Although both the former rule 1.7 and the current rule 1.7(b) allow a lawyer to undertake representation in circumstances when there is exists a concurrent conflict of interest, the lawyer should use extreme caution in deciding to undertake such representation. The lawyer must make an independent judgment that he or she can provide "competent and diligent representation" before the lawyer can even ask for consent to proceed. The court in subsequent proceedings can review such a judgment. See Fiandaca v. Cunningham, 827 F.2d. 825 (1st Cir. 1987).