Here is what we know about the recent developments related to the FBI's investigaiton into Hillary Clinton's use of a private email server while she was secretary of state. After an exhaustive investigation, the bureau concluded that although her email arrangement was risky and utterly foolish, it was not the sort of case that would be prosecuted, whether the person involved was a low-level bureaucrat or a candidate for president. Subsequently, in an unrelated investigation, the FBI found messages from Ms. Clinton on the laptop of the husband of one of her top aides, and, less than two weeks before the election, FBI Director James Comey decided to inform Congress of that fact.
Here is what we don't know. We don't know how many of the messages were from the period covered by the FBI investigation. We don't know whether any contained classified information, and, if so, whether they were materially different in any respect from the messages marked classified that the FBI had already found in its examination of Ms. Clinton's server. We don't know how many of the messages are duplicates of emails the bureau had already found during its previous investigation. We don't even know how many were actually from Ms. Clinton.
The reason we don't know any of these things — what you might call the most pertinent facts when it comes to Americans' efforts to make sense of this latest revelation before they vote — is because the FBI doesn't know. Officials only recently sought legal permission to examine the emails and have not yet received it, meaning agents had not begun reading them before Mr. Comey sent his letter to Congress. Nor is there any realistic possiblity that they will complete the investigation before the election.
What Mr. Comey's letter amounts to, then, is releasing highly prejudicial information about an investigation without any factual basis for suspicion that a crime has been committed. The only conceivable reason for doing so when and how he did was that he has faced intense criticism from Republicans for his decision this summer to recommend against charging Ms. Clinton and a fear that he, personally, would be criticized again. In a misguided attempt to protect his own reputation, he violated two of the Justice Department's cardinal rules: Don't comment on ongoing investigations and don't allow even the appearance of interfering in the electoral process.
Call the FBI and ask about any investigation, from routine tax fraud up to questions about whether Donald Trump aides have ties to Russian hackers trying to influence the election, and you'll get the same answer: The FBI does not comment on ongoing investigations. That's an enormously important rule because it prevents the government from using its powers to effectively convict people in the public eye who would never even face charges in court. The extent of the information Mr. Comey provided about this case already, in public statements and Congressional testimony, is highly unusual. FBI directors don't typically go around providing their personal opinions about the conduct of people against whom they recommend no charges. But when giving his testimony this summer, he was at least speaking from something resembling a complete set of facts and was doing so before Ms. Clinton had formally been nominated by the Democratic party.
To be clear, we consider Ms. Clinton's use of a home email server for official business while she was secretary of state to have been careless, foolish and reckless. For someone who was likely to make another run for president, it was downright stupid. Whatever she thought she was gaining in terms of convenience — or, more likely, in terms of protecting her privacy from public information requests — was not remotely worth the risk her choice entailed.
If Mr. Comey had new information that materially changed what was known about Ms. Clinton's email, or even a realistic belief that such information could be forthcoming before the election, there might have been some justification for him to have shared it with the public, FBI policies and practices notwithstanding. But what the FBI discovered and Mr. Comey felt compelled to share with Congress — and, hence, the entire electorate — adds nothing to the legal or policy implications of the story. It only changes the politics in a way that is entirely predictable. However he justifies his actions, one of the most powerful law enforcement officials in the country has put his thumb on the scale of this election. That's not something we do in this country.