In a second meeting, on February 14, Mr Trump is then reported to have asked Mike Pence, the vice president, and chief of staff Reince Priebus to leave the room before requesting that Mr Comey drop the FBI investigation into Mike Flynn, his disgraced former national security adviser.
Mr Comey was apparently appalled at the request.
And, a conscientious note-taker, as expected by someone in his role, he wrote it all down.
These memos, described to associates, are now being leaked to the media. And it is these documents which could form the basis of any impeachment hearing, if they are deemed to consist an obstruction of justice.
Bill Clinton and Richard Nixon both faced impeachment procedings in part due to obstruction of justice – although Nixon of course resigned before he could be impeached.