Investigators into Russian attempts to subvert American democracy grievously mistreated Gen. Michael Flynn, now convicted of perjury related to the investigation. Some of the prosecutors should themselves face professional punishment for their misbehavior.

As this site’s resident defender of special counsel Robert Mueller, I am obligated to insist that the investigators themselves uphold the same standards they would apply to others. Without excusing Flynn’s lies to investigators, a fair-minded observer can call foul on an obviously unfair, and perhaps unlawful, perjury trap.

Federal district judge Emmet Sullivan likewise seems quite perturbed by the latest information about the Flynn case. With Flynn’s sentencing imminent, Sullivan suddenly ordered prosecutors to produce any existent memoranda regarding their conduct of the interview in which Flynn lied.

And for good reason. The investigators’ treatment of Flynn, as described in a memo filed with the court by Flynn’s lawyers, looks like a textbook case of unethical entrapment.

The interview was set up directly via a phone call to Flynn from Andrew McCabe, who then was deputy director of the FBI. McCabe, by his own account, made it sound like an ordinary national-security-related briefing of the sort Flynn was accustomed to giving the FBI. Even though McCabe clearly knew that Flynn was a potential subject of investigation, he deliberately dissuaded Flynn from having attorneys present.

Moreover, when the agents arrived, they and Flynn both treated the meeting as rather informal, even “jocular,” and “the agents did not provide General Flynn with a warning of the penalties for making a false statement … before, during, or after the interview.” The agents’ decision not to so inform Flynn was made at the direct behest of McCabe because “they wanted Flynn to be relaxed.”

This is an absolute outrage.

Granted, it’s not certain that the ordinary requirement for a “ Miranda warning” were applicable in this situation because Flynn had not been detained by, nor was in the custody of, law enforcement. Yet in commonsense terms, what McCabe and his agents did was obviously entrapment. It may even have crossed the official legal line of entrapment to the effect that Flynn’s conviction might be thrown out. At first perusal, it appears to have done so.

Let’s be clear what this FBI perfidy does and doesn’t mean. First, it does not have any bearing on Mueller’s conduct of the investigation: The interview with Flynn occurred months before Mueller was appointed. And Mueller, pleased with Flynn’s cooperation, has recommended no jail time for the general. Flynn’s case is only a small part of Mueller’s overall investigation, which has been conducted “by the book” (as the expression goes). Second, it does nothing to invalidate, or make legally unusable, any other information Flynn provided Mueller’s team while cooperating. If Flynn provided evidence implicating others in misdeeds, that evidence is still good.

Third, though, this entrapment provides even more reason for McCabe himself to be investigated for wrongdoing. Again and again, it has been shown that McCabe acted not as the impartial enforcer of justice that a top FBI official should be, but rather as a partisan or ideological hack against conservatives in general or against Trump’s team in particular.

Fourth and finally, this might remove the status of “felon” from Flynn’s permanent record. A man with a distinguished military career, whose lie did not involve conduct that in itself was criminal and was less self-protective than it was a matter of political ham-handedness, perhaps merits some slack anyway. His reputation already has suffered; must his legal status also be permanently scarred?

Either way, McCabe’s behavior here appears shameful, well deserving of fierce condemnation.