ALL THE DIRECTOR'S MEN

There are at least 100 books about Richard Nixon on file at the Library of Congress. The way things are going, there will be just as many written about Oliver Stone's Nixon. The $42 million Disney movie has already been challenged for its historical accuracy, echoing the controversy that accompanied the filming of Stone's JFK in 1991. But while journalists are dithering over plot points, the director is concentrating on casting all the President's men. Besides Anthony Hopkins in the title role, the movie stars Paul Sorvino (Henry Kissinger), James Woods (H.R. Haldeman), J.T. Walsh (John Ehrlichman), Bob Hoskins (J. Edgar Hoover), Peter O'Toole (Richard Helms), Diane Ladd (Martha Mitchell), and Annabeth Gish (Julie Nixon Eisenhower). Stone is also trying to commandeer the likes of Ed Harris, Gary Oldham, and Kenneth Branagh for a cameo. To help the director avoid any further flap, we asked a few Watergate veterans to cast themselves. Judging from their choices-and the director's actual picks-don't be surprised if there are calls for Stone's impeachment before the film debuts. Watergate player: Alexander Haig. His casting choice: Mel Gibson. ''Audiences would never believe he was a sinister force. He isn't quite as good-looking as I am, so it wouldn't seem self-serving. And he's foreign born (Gibson is American), so no one could accuse him of wanting to be President.'' Stone's choice: Powers Boothe (Blue Sky).

Watergate player: John Dean. His casting choice: Kevin Costner. ''His acting is very honest, and that's something I've always tried to be.'' Stone's choice: David Hyde Pierce (Frasier).

Watergate player: G. Gordon Liddy. His casting choice: Tommy Lee Jones. Liddy liked him in Under Siege. ''He's very intense.'' Stone's choice: John Diehl (The Client). -Jeffrey Wells