Matthew Miller was director of the Justice Department’s public affairs office from 2009 to 2011.

FBI Director James B. Comey’s stunning announcement that he has directed investigators to begin reviewing new evidence in the Clinton email investigation was yet another troubling violation of long-standing Justice Department rules or precedent, conduct that raises serious questions about his judgment and ability to serve as the nation’s chief investigative official.

Comey’s original sin came in July, when he held a high-profile news conference to announce his recommendation that the Justice Department bring no charges against Hillary Clinton. In doing so, Comey violated Justice rules about discussing ongoing cases and, as I argued at the time, made assertions that exceeded FBI authority, recklessly speculated about matters for which there was no evidence, and upended the consultative process that should exist between investigators and prosecutors.

Comey argued that his news conference was necessary in a case of intense public interest, but as his actions in the months since have shown, the precedent he set has led only to increasingly problematic outcomes.

[James Comey needs to clean up his mess. Here’s what we need to know.]

On Oct. 28, the FBI announced new inquiries related to Hillary Clinton’s private email server. The Fix's Aaron Blake breaks down reactions to the announcement and explains why it matters to her presidential campaign. (Sarah Parnass/The Washington Post)

First, because Comey had already publicly discussed the investigation, he felt free to answer detailed questions about it before a congressional panel two days later. Comey’s description of not just the FBI’s legal reasoning but also the underlying facts of the case only provided more ammunition to critics on both sides. Notably, when Comey’s titular boss, Attorney General Loretta E. Lynch, appeared before a congressional panel later that month, she declined to follow his lead, citing Justice practices prohibiting her from doing so.

Then Comey decided to turn over the FBI’s investigative file to Congress, refusing to even consult with the State Department over what information should be redacted. When that wasn’t enough to satisfy critics, he publicly released the information in dribs and drabs that fueled repeated news cycles in the midst of the campaign.

With each step, Comey moved further away from department guidelines and precedents, culminating in Friday’s letter to Congress. This letter not only violated Justice rules on commenting on ongoing investigations but also flew in the face of years of precedent about how to handle sensitive cases as Election Day nears.

Justice traditionally bends over backward to avoid taking any action that might be seen by the public as influencing an election, often declining to even take private steps that might become public in the 60 days leading up to an election. For an example, in one case of which I am aware, the FBI opened an investigation into a high-ranking public official shortly before an election but delayed sending any subpoenas until after the election for fear that they might leak and unfairly tarnish the official. Indeed, that investigation ultimately concluded with no charges.

Comey’s subordinates have argued through anonymous quotes to reporters that he felt compelled to update Congress because of his previous explanations to them. But that just exposes how ill-advised his earlier statements were. Furthermore, even if he felt compelled to update Congress at some point, he could have followed Justice guidelines and done so after the election.

[The damage Comey’s bad timing could do]

Supporters of the FBI director also argue that he would have been criticized had he withheld this information until after the election. But he didn’t actually provide Congress or the public with any substantive information. Instead, he provided just enough detail to allow Republicans to make speculative charges about Clinton, but not enough to allow her to defend herself. In fact, in the hours since Comey’s letter was released, media outlets have reported often-contradictory details about what the FBI is actually examining, another inevitable result of his actions.

This entire episode has exposed a troubling character flaw that calls into question Comey’s very fitness to lead the FBI. He is without a doubt an outstanding lawyer and public servant. But as he has carefully nurtured his reputation for independence and integrity, he seems to have become intoxicated by the plaudits that have come his way. That praise has emboldened him to ignore the rules that apply to others, both because he believes in his own reputation and because he wants to thwart critics such as Republicans in Congress who might question it.

This case in particular has exposed how Comey’s self-regard can veer into self-righteousness, a belief that only he can fairly adjudicate the appropriateness of others’ conduct, and that the rules that apply to every other Justice Department employee are too quaint to restrict a man of his unquestionable ethics.

That is a dangerous trait. The director of the FBI has great power at his disposal. Congress has seen to fit to provide FBI directors with nearly unfettered independence, including a 10-year term designed to stretch beyond any one president’s tenure.

With that independence comes a responsibility to adhere to the rules that protect the rights of those whom the FBI investigates. Comey has failed that standard repeatedly in his handling of the Clinton investigation.