That's what Hillary's FBI files were about, blackmail against the Republicans to prevent anyone crossing any lines. Republicans were allowed to discuss issues, but not talk about Bill's nose surgery.
Hillary doesn't have FBI files on Trump, probably never thought to ask for it back then. Even so, they can't blackmail him. But he can say the things that we all knew about her but that were hidden by the press and complicit Republicans back then.
I remember sitting in the car after a gym workout in 96 listening to the radio news when Clinton had hit Dole with criticism. I said to myself, Dole you need to answer Clintoon. Bob Dole did not respond to Clinton's remarks ever. In a few days, Dole drops in the polls. Dick Morris years later noted the lack of response from Dole about the same event, and Morris wondered why Dole said nothing.