This is a thoughtful opinion on when a lawyer can ethically threaten another lawyer with disciplinary charges. Obviously, it is governed by New York law, not Illinois law. Illinois rule 8.4(g) provides that: “It is professional misconduct for a lawyer to present, participate in presenting, or threaten to present criminal or professional disciplinary charges to obtain an advantage in a civil matter.“
My advice on this issue is never to threaten any charges against anyone. There is a risk of a claim of extortion or a violation of Rule 8.4(g). If the misconduct is really serious, a lawyer must report it to the ARDC.
Edward X. Clinton, Jr.