The gravity of the issues raised by the events that led to national security adviser Michael Flynn’s resignation cannot be overstated or ignored. Revelations about Flynn’s contact with the Russians and reports indicating that he may have lied to the FBI about that contact may be only the tip of the iceberg. There’s an overwhelming view in our intelligence community that Russia tried to influence our election.

The American people, and indeed American democracy, require a thorough and independent investigation into what transpired and whether any criminal laws or constitutional precepts were violated. Such an investigation and any resulting prosecution would normally be carried out under the purview of the attorney general, as the nation’s chief law-enforcement officer with oversight of the Federal Bureau of Investigation. But in this case, given his deep and long-standing ties to President Donald Trump and many of Trump’s top advisers, Attorney General Jeff Sessions cannot lead such an investigation.

Sessions’s recusal is required by the Justice Department’s own rules and regulations. The department clearly states that “no employee shall participate in a criminal investigation or prosecution if he has a personal or political relationship with any person or organization substantially involved in the conduct that is the subject of the investigation or prosecution or any person or . . . has a specific and substantial interest that would be directly affected by the outcome of the investigation or prosecution.” It is beyond dispute that Trump has a number of specific and substantial interests that would be directly affected by the outcome of the investigation. The regulations define a political relationship as “a close identification with an elected official [or] candidate . . . arising from service as a principal adviser thereto or a principal official thereof.”

During the campaign, Sessions was identified by the Trump campaign and by Trump himself as a key adviser. Sessions was the first senator to endorse Trump, frequently appeared with him on the campaign trail and even served on the same campaign council as Flynn. Would he be able to impartially lead an inquiry into potential wrongdoing by the team that appointed him to his current post and with whom he has been closely allied? Certainly, the appearance of bias is unavoidable.

Most important, Sessions’s recusal from this matter is important not only to comply with the law but also to ensure that the public can have faith that the investigation is being conducted in a thorough and impartial way. Last week, the attorney general met with the president in the Oval Office, as his job requires. Until he recuses himself from this investigation, many Americans will remain suspicious about what they discussed. Did they talk about the ongoing investigation? Did the president try, in any way, to steer him away from the truth? A cloud will hang over every meeting and conversation between the president and attorney general until Sessions recuses himself.

Because administration officials did not reveal Flynn’s prevaricating about his contacts with Russia for weeks, acknowledging them only after they were exposed by the media, they have made it extremely difficult for the American people to believe that they will endeavor to get to the bottom of the issues at hand. Removing a political ally from running the investigation is absolutely necessary to “assure the public the matter will be handled without partisanship.” Anything short of a full recusal by Sessions will jaundice the investigation and violate Justice Department rules.

As then-Sen. Sessions wrote, with others, in calling for the recusal of then-Attorney General Loretta E. Lynch in the matter of former secretary of state Hillary Clinton’s emails: “When a high public official is accused of serious wrongdoing and there is a sufficient factual predicate to investigate it is imperative the investigation be thorough, with dispatch and without partisanship. . . . The appropriate response when the subject matter is public and it arises in a highly-charged political atmosphere is for the Attorney General to appoint a Special Counsel of great public stature and indisputable independence to assure the public the matter will be handled without partisanship.” Attorney General Jeff Sessions should take the words of Sen. Jeff Sessions to heart.

Special to The Washington Post · Chuck Schumer