Just seven days after taking office, President Trump says, he had a private dinner in the White House with FBI Director James B. Comey. Trump asked whether Comey would “let me know, am I under investigation?” According to Trump, Comey answered, “You are not under investigation.”

Comey’s allies dispute that the conversation happened that way; instead, they say, Comey refused to pledge his personal loyalty to Trump, a contention the White House, in turn, disputes.

But as a matter of ethics, if Trump is telling the truth, is there a problem with a president asking the head of the FBI about the status of an investigation into the president’s campaign?

Trump’s aides may not see it this way, but the short answer is yes.

The question reflects a conflict of interest that the president has: a conflict between his constitutional duty to take care that the laws of the nation are faithfully executed, and a personal desire to avoid any potential legal or political jeopardy. And Trump’s question also makes more acute a conflict of interest that the FBI director has: the conflict between a duty to handle criminal investigations impartially (even an investigation that implicates or angers the president) and his personal desire to keep his job. As we’ve seen this week, the president has the authority to fire the FBI director.

Which means a future FBI director who wants to keep his job may feel pressure to tell the president what he wants to hear: No, Mr. President, you are not under investigation.

Implicit in this situation is the potential for coercion. By even asking the question, the president may be pressuring the director to provide the desired answer, either by limiting the scope of any investigation that could implicate the president or by ending the investigation entirely.

These scenarios are not mere academic musings. We need only look at the history of the Watergate investigation to see what happens when the Justice Department allows the White House to keep tabs on a criminal investigation.

While the Watergate burglary eventually led to the appointment of an independent prosecutor, initially, the Justice Department’s criminal division handled the investigation. The head of that division, Henry Peterson, kept the Nixon White House informed of the progress of the investigation. He assured White House Counsel John Dean that there would be “no fishing expedition,” explaining that the prosecutor assigned to the case “knows better than to wander off beyond his authority into other things.”

The Senate Select Committee on Presidential Campaign Activities found that Peterson had served as “a conduit for a constant flow of information from the grand jury and the prosecutors” to the White House, and that his “conduct raised a serious question as to whether high Department of Justice officials can effectively administer criminal justice where White House personnel, or the President himself, are the subjects of the investigation. The conflict of interest is apparent …”  (emphasis added).

The House Judiciary Committee’s first article of impeachment against President Richard M. Nixon cited him for “interfering or endeavoring to interfere with the conduct of the investigation by the Department of Justice.”

It was this history that led the Justice Department to adopt a broad policy strictly limiting its communications with the White House about pending criminal investigations. These limitations come in two forms: when such communications are permitted, and who can do the communicating.

First, when: The Justice Department may communicate with the White House about a pending criminal investigation only when that communication “is important for the performance of the President’s duties and appropriate from a law enforcement perspective.”

Second, who: Only two Justice Department officials are authorized to initiate such communications with the White House: the attorney general and deputy attorney general. (That’s why then-U.S. Attorney Preet Bharara avoided taking a phone call from Trump in March, instead informing Attorney General Jeff Sessions of the call.) By restricting so severely the number of officials who can have White House contacts, the Justice Department limits the number of those communications and can better control of them.

The breadth of this Justice Department restriction — applying broadly to all criminal investigations, not just those that clearly implicate the White House — reflects both the difficulty of knowing in advance where an investigation may lead and the importance of ensuring that criminal investigations are not tainted by White House interference.

So again, if it really happened the way the president says it did, Trump’s decision to question Comey about the FBI’s investigation of his campaign was not normal.

At best, it suggests that Trump does not understand that criminal investigations must be insulated from the exercise of raw political power. But more likely, the question reflects Trump’s desire to exercise his political power to control a criminal investigation that he finds inconvenient — as does his statement to NBC News that when he decided to fire Comey, he said to himself, “You know, this Russia thing with Trump and Russia is a made-up story.”

Congress, the courts and the people responded forcefully when we learned that Nixon had covertly attempted to exercise his political power to control a criminal investigation. We have yet to see whether Congress, the courts and the people will respond just as forcefully now that it appears as though Trump is overtly attempting to do the same.

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