Frost/Nixon/WMG

Frost dreamed the phone call.
Late in the film, Frost is alone in his hotel room at night when Nixon calls him and rants in an unhinged manner. When they meet in person, Nixon can't remember the call. We're supposed to believe that Nixon's drunkenness was affecting his memory, but it's just as likely that Frost fell asleep and dreamed the whole thing. It would be less of a departure from the real-life events, and it would also explain why Nixon cared so much about Frost's past.

The film is set in an Alternate Universe, and Nixon's phone call is the Point of Divergence
The film isn't relating Real Life events. Frost didn't nail Nixon in Real Life. The phone call was the first major departure from reality.
 * He didn't? He certainly got him to say the same things on tv that he did in the movie...
 * True, but it wasn't a "damning admission of guilt"--it was a carefully calculated PR move on Nixon's part.

The film was originally going to be Brokeback Mountain, with political figures instead of cowboys before Executive Meddling
Just look at the title dammit!
 * In the extended dvd release this will still be the case
 * At least it wasn't the *ahem* other type of Slash. Although some people might like to see that...