Law enforcement officials never fully investigated Mr. Trump’s own relationship with Russia, even though some career F.B.I. counterintelligence investigators thought his ties posed such a national security threat that they took the extraordinary step of opening an inquiry into them. Within days, the former deputy attorney general Rod J. Rosenstein curtailed the investigation without telling the bureau, all but ensuring it would go nowhere.

Michael J. Schmidt

“We opened this case in May 2017 because we had information that indicated a national security threat might exist, specifically a counterintelligence threat involving the president and Russia. I expected that issue and issues related to it would be fully examined by the special counsel team…

It was first and foremost a counterintelligence case. Could the president actually be the point of coordination between the campaign and the Russian government? Could the president actually be maintaining some sort of inappropriate relationship with our most significant adversary in the world?

Andrew McCabe, then acting director of the FBI

Sessions’s recusal does not seem meaningful since we know that he took part in a White House meeting at which Trump demanded that James Comey, the former F.B.I. director, be fired. And Rosenstein himself is tainted.

He was also in that meeting and seems to have obeyed the president’s orders to gin up a memo making it appear as though Comey was being dismissed over the investigation of Hillary Clinton’s emails. The White House, in fact, tried to put the entire responsibility for Comey’s dismissal on Rosenstein, until Trump blurted out that he was motivated by the Russia inquiry and had decided to fire Comey before the meeting.

Andrew Rosenthal, New York Times