Cokie Roberts and Steven V. Roberts

FBI Director James Comey knew exactly what was going to happen.

He was already a controversial figure in the presidential campaign. His statement this summer, that Hillary Clinton had been "extremely careless" in handling her government email accounts, has been repeated endlessly in Donald Trump ads.

And now he's done it again. He wrote a letter to Congress, less than two weeks before the election, saying that a new trove of emails discovered on the computer of Anthony Weiner -- the estranged husband of Clinton aide Huma Abedin -- may be relevant to the Clinton case, which had been suspended months ago.

There was no hint of wrongdoing on Clinton's part. When Comey wrote his letter, neither he nor any of his investigators had evaluated the Weiner emails. And yet he had to know that his letter -- no matter how carefully couched -- would immediately be distorted and exaggerated by the Trump campaign.

And it was. The FBI director had provided yet more fodder for Trump's attacks. But this time, it was not Hillary Clinton who was "extremely careless." It was Comey himself.

Comey cannot plead ignorance. He knew the rules. He knew that very clear Justice Department guidelines prohibit doing precisely what he did: injecting the country's most powerful law enforcement agency into a political campaign.

As The Washington Post reported, in early October, Comey had specifically invoked those guidelines in declining to join a statement issued by the Director of National Intelligence and the Department of Homeland Security. The statement blamed Russia for cyber attacks aimed at influencing the American elections, but Comey thought "it was too close" to Election Day for him to get involved.

Even many Republicans have joined the chorus condemning Comey's misjudgment. George J. Terwilliger III, deputy attorney general under George Bush 41, told The New York Times: "There's a longstanding policy of not doing anything that could influence an election. Those guidelines exist for a reason. Sometimes that makes for hard decisions. But bypassing them has consequences."

Larry Thompson, deputy attorney general under Bush 43, co-authored an op-ed piece in the Post that asserted, "It is antithetical to the interest of justice, putting a thumb on the scale of this election and damaging our democracy."

Joe Walsh, a former Congressman and fiercely conservative radio host, tweeted about Comey: "What he just did 11 days b4 the election is wrong & unfair to Hillary."

There's no evidence that Comey was deliberately trying to help Trump, and charges that he violated the Hatch Act -- which bars political activity by federal employees -- seem unfair. But Comey was guilty of a different sin: placing his own ego and his concern for his personal reputation ahead of his responsibility to the FBI or the democratic process.

As Matthew Miller, a Justice Department spokesman during Barack Obama's first term, wrote in the Post, "This case in particular has exposed how Comey's self-regard can veer into self-righteousness." The FBI director seems to believe "that the rules that apply to every other Justice Department employee are too quaint to restrict a man of his unquestionable ethics."

Comey's ill-advised letter would not be so damaging to Clinton if she had not, throughout her whole career, earned her reputation for cutting corners and bending rules. The trope that all her troubles are caused by a "vast right-wing conspiracy" and a media that unfairly exaggerates her flaws is simply not true.

The Clintons have always given their enemies plenty of ammunition: her misguided use of a private email server as secretary of state; the appearance of tawdry influence-peddling that clings to the Clinton Foundation; her greedy determination to rake in millions of dollars in paid speeches from institutions that were clearly currying favor with a possible future president.

Perhaps worst of all: Bill Clinton's egregious decision to meet with Attorney General Loretta Lynch last June while the Justice Department was concluding its investigation of his wife's handling of classified emails. As a result of his stupidity, Lynch has little leverage over Comey.

We won't know until next week whether Comey has altered the course of the election. His letter will probably cause few voters to change sides, but recent polling indicates that some Democrats are discouraged, while Republicans are energized. And intensity and turnout matter in close races -- for the Senate as well as the White House.

But we do know this: In trying to protect his personal reputation, and the reputation of his agency, James Comey has badly damaged both.

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