RPC 1.9 bars representation without consent of former client - NJ Supreme Court

In Twenty First Century Rail v. NJ Transit the New Jersey Supreme Court has held that in analyzing a successive representation conflict under RPC 1.9 written consent of the former client is a necessity.  Absent that representation is barred:

"In this appeal, we consider whether an attorney who was retained to provide advice to a client in connection with a construction project violated RPC 1.9 by subsequently undertaking the representation of another party that was involved in the construction project whose interests were adverse to those of the former client.  Both the trial court, and the Appellate Division in its published opinion, TwentyFirst Century Rail Corp. v. N.J. Transit, 419 N.J. Super. 343 (App. Div. 2011), concluded that the RPC did not bar the attorney from undertaking the subsequent representation and therefore declined to disqualify him and his firm from the matter.  Because our analysis of the project, the relationship among the parties to the litigation, and the role played by the attorney, demonstrates that the subsequent representation was prohibited by the clear terms of RPC 1.9, we reverse the Appellate Division’s judgment.
In clear language, RPC 1.9(a) begins with a prohibition that precludes an attorney from engaging in the representation of an adverse client in the same matter unless the former client consents in writing.  RPC 1.9(a).  Therefore, if the prior and the subsequent matters are indeed the same, the representation, absent written consent of the former client, is prohibited.  In that circumstance, we need not conduct the inquiry into whether the matters are substantially related[.]"