What if a lawyer wanted to represent a Colorado-based business that sells marijuana in compliance with state law but in violation of federal law?

As discussed by Prof. Anita Bernstein at the Legal Ethics Forum: "A federal law, governing pretty much everyone, prohibits the possession and use of marijuana—even by medical patients with scripts from doctors. Some state laws defy this prohibition. DoJ has declared that, for now, it will look the other way from well-behaved adult users in those states. And every jurisdiction has a counterpart to Model Rule 1.2(d), which says lawyers who “counsel a client to engage, or assist a client, in conduct the lawyer knows is criminal…” are subject to discipline." So can a lawyer ethically represent a Colorado-based business that sells marijuana in compliance with state law but in violation of federal law? Go here for the full discussion.