Although we acknowledge that Comey faced a difficult situation with unattractive choices, in proceeding as he did on October 28 [sending a letter to Congress re the discovery of Clinton emails on Anthony Weiner's computer], Comey made a serious error of judgment. (371)

I completely agree.

1. FBI and Department Norms and Policies

Comey had ample guidance in longstanding Department and FBI policies and norms regarding making public statements about pending investigations and taking actions that might affect elections.

Absolutely.

The “stay silent” principle...

The“60-day rule,” “take no action" within 60 days of an election (372)

In reaching our conclusion about the October 28 letter, we found the testimony of Deputy Assistant Attorney General George Toscas to be on point:

One of the things that I tell people all the time...the institution has principles and there’s always an urge when something important or different pops up to say, we should do it differently or those principles or those protocols—we might want to deviate because this is so different. But the comfort that we get as people, as lawyers, as representatives, as employees and as an institution, the comfort we get from those institutional policies, protocols, has, is an unbelievable thing through whatever storm, you know whatever storm hits us, when you are within the norm of the way the institution behaves, you can weather any of it because you stand on the principle. And once you deviate, even in a minor way, and you’re always going to want to deviate. It’s always going to be something important and some big deal that makes you think, oh let’s do this a little differently. But once you do that, you have removed yourself from the comfort of saying this institution has a way of doing things... (374)

Comey’s description of his choice as being between “two doors,” one labeled “speak” and one labeled “conceal,” was a false dichotomy. The two doors were actually labeled “follow policy/practice” and
“depart from policy/practice.”

 He stated, instead, that he had previously offered “maximal transparency” because that “enhances the credibility of the Justice enterprise,” and that maintaining that transparency required him to update his July statement in October.

If so, the problem originated with Comey’s elevation of “maximal transparency” as a value overriding, for this case only, the principles of “stay silent” and “take no action” that the FBI has consistently applied to other cases. 

The Department and the FBI do not practice “maximal transparency” in criminal investigations. It is not a value reflected in the regulations, policies, or customs guiding FBI actions in pending criminal investigations. To the contrary, the guidance to agents and prosecutors is precisely the opposite—no transparency except in rare and exceptional circumstances due to the potential  harm to both the
investigation and to the reputation of anyone under investigation. (373)

Okay, enough. Clear as crystal, right? I think so. 

I'm a lawyer and good lawyers always play devil's advocate. That's what I'm doing here. In my long ago life as a political scientist in training I read every book available at the time on the Cuban Missile Crisis. Essence of Decision was the title of Graham Allison's book. During those excruciating thirteen days in October, 1962 nerves got frayed. I remember one such. An administration official, I think it was Defense Secretary McNamara, since the statement is something he would have made, went down to the Secretary of the Navy's office and asked him what he would do if the Soviet ships ran the "quarantine" around Cuba. "It's all in here, Mr. Secretary, it's all in here", lovingly patting a thick stack of Navy regulations. Quoth McNamara,

"I DON'T GIVE A GOOD GODDAMN WHAT JOHN PAUL JONES WOULD HAVE DONE, I WANT TO KNOW WHAT YOU ARE GOING TO DO NOW!"

It was a "comfort" to the Navy Sec to be able to pat that stack of regulations; he didn't have to decide, he could look up precedent and and have the precedent decide for him. The DOJ's policies and principles are "comfort" to DAG Toscas. Neither the Navy Sec nor Toscas was wrong. They were elevating process over result. Secretary McNamara was not wrong. He was elevating result over process. The Cuban Missile Crisis was a "rare and unusual circumstance"; it would have justified departure from the precedent set by John Paul Jones in a different century, especially one without the possibility of The End via a nuclear exchange between the U.S. and the Soviet Union. McNamara was not wrong. 

It follows that James Comey was not wrong ab initio. Comey did not elevate result over process as McNamara did, he elevated another principle, one unknown in criminal law enforcement, "maximal transparency," above those other established principles. But Comey did this for a result: to protect his agency, the FBI. Not in the name of justice nor to protect the Justice Department: of, by, and for the FBI. Comey considered the Clinton email investigation in the middle and at the very end of a presidential election to be that "rare and unusual circumstance" warranting a new principle. But when you deviate from precedent and policy, you are substituting your judgment for the judgment of the ages, and you better be right.

All good policy has elasticity for judgment by humans, otherwise it is not persuasive precedent but binding decision-making by the long dead, or in this age of AI, by computer programs. The Department of Justice's principles, "stay silent", and the "60-day rule" have such elasticity. The "rare and unusual circumstance" justifies, in the judgment of decision makers, departure from ordinary process. 

In this OIG autopsy, and in my personal opinion, James Comey's judgment was very wrong. But how can we be sure? The OIG says because Comey deviated from established process and inserted a new, unprecedented principle. If he had withheld notification of Congress would Hillary Clinton have been elected president? That question upsets the order of legal and democratic rule, process over result. But Comey elevated result over process, too.  Comey's errors were those of judgment over established process, and result over any process. Hillary Clinton thinks that Comey's October 28 letter to Congress cost her the election. She is not wrong to focus on result, but she doesn't know and no one knows. Keeping the established order, process over result, is "comforting"; if process is followed the result is always "right." Except when it's not.