Is it a violation of the duty of loyalty for an attorney to act in the absence of the client's consent?

One aspect of this high and stringent obligation is the attorney's duty to protect the client in every possible way. Consequently, it is a violation of the duty of loyalty for the attorney to assume a position adverse or antagonistic to his or her client without the client's free and intelligent consent given after full knowledge of all the facts and circumstances. (Flatt v. Superior Court, supra, 9 Cal.4th at p. 289, 36 Cal.Rptr.2d 537, 885 P.2d 950.) A client who learns that his or her lawyer is also representing a litigation adversary, even in a wholly unrelated matter, cannot be expected to sustain the level of confidence and trust in counsel that is one of the foundations of the professional relationship. (Id. at p. 285, 36 Cal.Rptr.2d 537, 885 P.2d 950.) Thus, even though the simultaneous representations may have nothing in common, and there is no risk that confidences to which counsel is a party in the one case have any relation to the other matter, per se or automatic disqualification is required in all but a few instances. (Id. at p. 284, 36 Cal.Rptr.2d 537, 885 P.2d 950.)