When FBI Director James Comey stepped to the lectern to deliver his remarks about Hillary Clinton on Tuesday, he violated time-honored Justice Department practices for how such matters are to be handled, set a dangerous precedent for future investigations and committed a gross abuse of his own power.

Some have praised Comey’s remarks as much-needed truth-telling from a fearless, independent law-enforcement authority, an outcome Comey no doubt had in mind. But in fact, his willingness to reprimand publicly a figure against whom he believes there is no basis for criminal charges should trouble anyone who believes in the rule of law and fundamental principles of fairness.

Justice Department rules set clear guidelines for when it is appropriate for the government to comment about individuals involved in an ongoing investigation, which this matter was until prosecutors closed it Wednesday. Prosecutors and investigators can reassure the public that a matter is being taken seriously, and in some rare cases can provide additional information to protect public safety, such as when a suspect is loose and poses a danger.

And when the department closes an investigation, it typically does so quietly, at most noting that it has investigated the matter fully and decided not to bring charges.

These practices are important because of the role the Justice Department and FBI play in our system of justice. They are not the final adjudicators of the appropriateness of conduct for anyone they investigate. Instead, they build cases that they present in court, where their assertions are backed up by evidence that can be challenged by an opposing party and ultimately adjudicated by a judge or jury.

In a case where the government decides it will not submit its assertions to that sort of rigorous scrutiny by bringing charges, it has the responsibility to not besmirch someone’s reputation by lobbing accusations publicly instead. Prosecutors and agents have followed this precedent for years.

In this case, Comey ignored those rules to editorialize about what he called carelessness by Clinton and her aides in handling classified information, a statement not grounded in any position in law. He recklessly speculated that Clinton’s email system could have been hacked, even while admitting he had no evidence that it was. This conjecture, which has been the subject of much debate and heated allegations, puts Clinton in the impossible position of having to prove a negative in response.

In several instances, Comey made assertions that are outside the authority of the FBI. He inserted himself into a long-standing bureaucratic battle between the State Department and the FBI and intelligence agencies, making claims about classification practices at the State Department that do not fall under his jurisdiction. He raised the possibility of administrative sanctions that could be taken, another decision that is not his to make – any such sanctions, if appropriate, would be decided by the State Department, not the director of the FBI.

He also substituted his judgment for that of prosecutors. Career prosecutors at Justice have been working hand in hand with FBI agents on the case, even joining the interview with Clinton. While it is hard to imagine they would have reached a different conclusion about the appropriateness of charges, they deserved the ability to make that decision privately, in consultation with the FBI, rather than hear the agency’s recommendation at the same time the public did.

Comey argued that his statement was appropriate because this case was a matter of unusual public interest. But the department investigates cases involving extreme public interest all the time – suspected terrorist acts, alleged civil rights violations by police and possible crimes by financial institutions, for example. It is for precisely these situations that the rules exist, so that the department cannot speak outside the bounds of court when it does not bring charges.

Imagine a situation in which Barack Obama’s Justice Department investigates major conservative activists such as the Koch brothers for possibly violating the law, but finding no reason to bring charges, the attorney general holds a news conference to outline all of the ways in which she finds their conduct deplorable. A Republican attorney general declining to bring charges against union officials but publicly excoriating their behavior would be similarly objectionable.

While Clinton shouldn’t have received special treatment, she does not deserve worse treatment from her government than anyone else, either. Yet by inserting himself into the middle of a political campaign and making unprecedented public assertions, that is exactly what Comey provided.

The entire exercise seemed designed to protect Comey’s reputation for integrity, while not actually demonstrating integrity. Real integrity is making a decision, conveying it in the ordinary channels, and then taking whatever heat comes. Generations of prosecutors and agents have learned to make the right call without holding a self-congratulatory news conference to talk about it. Comey just taught them a different lesson.

(c) 2016, Special to The Washington Post · Matthew Miller