How long has Mueller known there was no Trump-Russia collusion?

In order to get the FISA warrants, the Justice Department and the FBI had had to allege that there was probable cause to believe former Trump adviser Carter Page was an agent of Russia. Under FISA law, that requires alleging that he was knowingly involved in clandestine activity on behalf of Russia, and that this clandestine activity involved probable violations of American criminal law – offenses such as espionage. Yet, despite the fact that this representation was made four times in sworn “verified” applications, Mueller never charged Page with a crime – not espionage, not false statements, nothing.

When Special Counsel Mueller closed his investigation last week, he almost certainly knew for about a year and a half that there was no collusion case. Indeed, the indictments that he did bring appeared to preclude the possibility that the Trump campaign conspired with the Kremlin.

Yet the investigation continued. The Justice Department and the special counsel made no announcement, no interim finding of no collusion, as Trump detractors continued to claim that a sitting American president might be a tool of the Putin regime. For month after month, the president was forced to govern under a cloud of suspicion.