I responded by pointing out that, while plaintiffs are prevented from using the 5th as a shield in civil cases, in a bar proceeding, the court has held that no penalty can be applied to a party invoking the 5th. That would include, in my recollection, adverse inferences and similar penalties. I believe that the court has held that such administrative proceedings are "quasi-criminal" in nature, and thus, you must make no adverse inference from silence, just as you can make no adverse inference from silence in a criminal case.
Your initial post concluded, "So should he take the Fifth in the disciplinary proceedings, Nifong would be risking an adverse inference that could be quite hazardous to his license to practice law in North Carolina.". I don't think that is correct, and the reason is, I don't think that a bar discipline proceeding is considered a "civil" proceeding to which your authorities apply, but a "quasi-criminal" one. I think that's the terminology used, anyway.
So, what we are on the same page on is that you can't plead the 5th in a civil action in which you are affirmatively trying to prove something, at least without consequences. But where we seem to be disagreeing is whether a state bar proceeding, such as the one against Nifong, is one of those types of actions. I think he can plead the 5th, and there will be no negative inference or issue preclusion--the state will just have to prove its case. However, if Nifong does testify, he will have to answer any and all questions--you can't just testify as to the good stuff and then clam up.
If you have case law subsequent to the Supreme Court's decision to apply the 5th amendment to administrative proceedings, such a bar discipline actions, which indicates that a bar discipline action is a civil action at which an adverse inference may be drawn against someone who invokes the privilege, I would love to see it. I'd be happy to be wrong, because I agree with you that the court, for the millionth time in the last century, exceeded its mandate in extending rights beyond their boundaries.
I've never seen such a case, and would very much like to read it, because this is an important issue. I can tell you this, though: In Baxter v. Palmigiano, 425 U.S. 308, 320 (1976), the Court expressly held: "The short of it is that permitting an adverse inference to be drawn from an inmate's silence at his disciplinary proceedings is not, on its face, an invalid practice" under the Fifth Amendment.
In so holding, the Court noted that "[p]rison disciplinary hearings are not criminal proceedings," id. at 316, further explaining: "The prevailing rule [is] that the Fifth Amendment does not forbid adverse inferences against parties to civil actions when they refuse to testify in response to probative evidence against them: the Amendment 'does not preclude the inference where the privilege is claimed by a party to a civil cause.'" Id. at 318 (quoting 8 J. Wigmore, Evidence § 2272 at 439 (McNaughton rev. 1961)) (U.S. Supreme Court's emphasis).
Now I don't know about you, but my guess is that the prison disciplinary proceeding at issue in Baxter, which resulted in the accused inmate-defendant being subjected to what the Court characterized as "'punitive segregation' for 30 days," as well as a downgrade in his "classification status," id. at 313, was quite a bit more "quasi-criminal" than any attorney disciplinary proceeding, even one that resulted in an attorney's disbarment.
For these reasons, any subsequent Supreme Court decision holding that because attorney disciplinary proceedings are "quasi-criminal" in nature, no adverse inference (much less total issue preclusion) can be drawn from an attorney's invocation of the Fifth Amendment either during discovery or at trial, would be a significant departure from Baxter, which would, of necessity, have to be distinguished. Maybe this has indeed occurred (and if so, it would certainly be yet another instance in which the Court "exceeded its mandate in extending rights beyond their boundaries" as you noted), but at this point, I am not aware of such a case.
If you can specifically identify the case to which you are referring, it would help clear this up. Otherwise, I think the many cases I have cited and quoted provide at least some support for my argument.
Meanwhile, when I have a chance, I'll Shepardize Baxter to see if it's been distinguished in a subsequent attorney disciplinary case decided by the U.S. Supreme Court. Meanwhile, perhaps you can dig up the case you're remembering. Does that sound like a workable plan?