Evidence? Really? Trump is so behind the times. Evidence is a 'last century' thing. Today, 'evidence' is only an after the fact procedural issue, once guilt has already been established. And evidence today can be anything. All the Dems have to do is to find someone who was around back then to claim, even if they have to lie, that they heard about it, or even saw it happen. That will close the case.
These days, the accusation itself is proof of guilt regardless of any old fashion ideas of evidence or proof.