The author, a lawyer in Washington, D.C., served in the United States Department of State from 2011-2014.

FBI director James Comey was criticized last week for refusing to comment publicly, or even in a classified setting, on whether the FBI is investigating Donald Trump’s possible connections to Russia. While we understand that emotions are running high, it is time to reaffirm longstanding bureau policy. The FBI will not comment on ongoing investigations of anyone not named Hillary Clinton.

Perhaps the FBI’s critics fail to understand the rationale for this policy. An investigation is just that—an investigation, not a conclusion, or even an accusation of guilt. Were the FBI to comment publicly on investigations of people not named Hillary Clinton, the public might infer, improperly and without evidence, that the person is guilty.

As any high school civics student knows, our government sets a high bar for tarnishing someone not named Hillary Clinton’s reputation with allegations of criminal conduct. Before the government can even publicly accuse someone not named Hillary Clinton of a crime, a prosecutor first submits the allegations in secret to a grand jury, which must vote to indict him or her.

Then the person not named Hillary Clinton is entitled to a public trial by jury of their peers. Prosecutors must convince the jurors, unanimously, that the person not named Hillary Clinton is guilty beyond a reasonable doubt. It’s not enough if the accused is merely very likely to be guilty—to convict in the US, there can be no reasonable doubt. If they’re not named Hillary Clinton.

These procedures relate to another FBI policy designed to protect the integrity of American elections. When candidates for high office are suspected of crimes, it puts the FBI in a bind.

On the one hand, voters are entitled to know the facts about candidates that they might vote for. On the other hand, in the absence of a conviction or even compelling evidence, voters might improperly infer that a candidate is untrustworthy based merely on partial facts or allegations.

For this reason, the FBI has for decades, across both Republican and Democratic administrations, followed a longstanding practice: The FBI will not take any action in the 60 days before an election that might affect the electoral prospects of someone not named Hillary Clinton.

In fact, during the 60-day period, the Department of Justice may not even seek grand jury indictments for candidates not named Hillary Clinton. To do so could leave voters casting ballots on the basis of mere allegations instead of proven facts.

For instance, over the summer of 2016, the FBI was provided intelligence from a reliable source that Republican candidate Trump’s campaign had been communicating improperly with Russian intelligence services, and may be subject to ongoing blackmail by a hostile foreign power. If true, Trump and his associates may be guilty of serious crimes.

But without more evidence, and because even Trump’s most vocal critics do not allege that he is named Hillary Clinton, it would have been completely inappropriate for the FBI to comment on the opening of an investigation of Trump.

Unless new evidence emerges that Trump has in fact called himself Hillary Clinton, at minimum as a nickname, criticism of the bureau in this case is simply misplaced.

These answers may not satisfy everyone, but we hope critics can see past their personal grievances and appreciate the FBI’s logic. The bureau has been given the solemn charge of enforcing the law impartially. Critics should ask themselves whether their preferred course of action could unwittingly tarnish innocent Americans, undermine our electoral system, or even politicize the administration of justice itself.