Matthew Miller, former director of DOJ's public affairs office, offers what I think is a
persuasive case that Comey has strayed from well-established practice to protect the FBI's (and more pointedly, his own) reputation:
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.
. . . 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.
I agree that Comey was in a no-win situation: He'd be attacked politically no matter what he did. But according to the reports I've seen, that's the sort of grief it's the FBI Director's job to take.
It's extraordinary for the FBI Director to wade right into the middle of a presidential election. Based on what's been publicly reported, there doesn't seem to be any equally extraordinary justification for that. If it was a desire to remain above the fray that motivated him, Comey may have made a serious misjudgment.