Lawyers should NOT represent clients with conflicting interests
The reason for the prohibition is found in the relation of attorney and client, which is one of trust and confidence of the highest degree. A lawyer becomes familiar with all the facts connected with his client's case. He learns from his client the weak points of the action as well as the strong ones. Such knowledge must be considered sacred and guarded with care. No opportunity must be given him to take advantage of the client's secrets. A lawyer must have the fullest confidence of his client. For if the confidence is abused, the profession will suffer by the loss thereof.Meanwhile, in Hornilla v. Salunat,[4] the Supreme Court explained the test to determine the existence of conflict of interest:
There is conflict of interest when a lawyer represents inconsistent interests of two or more opposing parties. The test is "whether or not in behalf of one client, it is the lawyer's duty to fight for an issue or claim, but it is his duty to oppose it for the other client. In brief, if he argues for one client, this argument will be opposed by him when he argues for the other client." This rule covers not only cases in which confidential communications have been confided, but also those in which no confidence has been bestowed or will be used. Also, there is conflict of interests if the acceptance of the new retainer will require the attorney to perform an act which will injuriously affect his first client in any matter in which he represents him and also whether he will be called upon in his new relation to use against his first client any knowledge acquired through their connection. Another test of the inconsistency of interests is whether the acceptance of a new relation will prevent an attorney from the full discharge of his duty of undivided fidelity and loyalty to his client or invite suspicion of unfaithfulness or double dealing in the performance thereof.
The rule prohibiting conflict of interest applies to situations wherein a lawyer would be representing a client whose interest is directly adverse to any of his present or former clients.[5] It also applies when the lawyer represents a client against a former client in a controversy that is related, directly or indirectly, to the subject matter of the previous litigation in which he appeared for the former client.[6] This rule applies regardless of the degree of adverse interests.[7] What a lawyer owes his former client is to maintain inviolate the client's confidence or to refrain from doing anything which will injuriously affect him in any matter in which he previously represented him.[8] A lawyer may only be allowed to represent a client involving the same or a substantially related matter that is materially adverse to the former client only if the former client consents to it after consultation.[9]
[1] Orola v. Ramos, A.C. No. 9860, September 11, 2013.
[2] Quiambao v. Bamba, 505 Phil. 126, 133 (2005).