I think the journalists have done that job efficiently. He was definitely a binge drinker.
That isn't illegal and the senate must decide if it thinks he perjured himself by downplaying it, or whether he was candid enough for them to give him a pass. We both know where that goes.
But the alcoholic soil of the sexual assault(s) now looks genuine and hard to argue against. He drank in measures which may easily have created blank periods in his memory. The FBI isn't really needed to prove that. The witness testimony is public.
It really comes down to whether his behaviour when blotto was aggressive - and then sexually aggressive - and whether there are witnesses to it. If they find he was aggressive when drunk, the leap between drunken aggression and sexual assault is small and hard to defend against when he claims he has had no memory lapses and was always in control of himself.
The more knowledge we receive, the more his own memory appears unreliable.