Washington vet Elizabeth Drew, who has written two books on Richard Nixon, has a terrific piece over at Huffington Post highlighting the considerable liberties that Frost/Nixon took with historical fact. She confirms, for instance, a point I made in my review about the gulf between Frank Langella's portrayal of  Nixon and the man himself:

Langella wreaks the magic of not just imitating Nixon but becoming him before our eyes, but this is not the true Nixon. The one we meet in the movie is too mellow, too jokey. There are only flashes of the bitterness that consumed and ultimately destroyed him.... Langella deftly shows that Nixon was a strange man, awkward with small talk, uneasy with people, but Langella's Nixon becomes an almost sympathetic figure, and also a jokey one, the one we most want to see, in order to have more laughs. But Nixon wasn't funny. And he certainly wasn't the likeable figure of Frost/Nixon. (Yes, of course, some people liked him, but not very many, and not even his dog.) He was a tragic Shakespearean figure, often out of control (and drunk), and, it seemed, more than a little mad (his aides never knew which orders were even intended, not least should be carried out), brought down by his flaws: he would have made for excellent drama, if not as much entertainment.

She also makes the interesting point that the Frost interviews were far from the contest that "only one man could win" that was portrayed in the film. In fact, Nixon and David Frost were business partners, both committed to whatever would get ratings--in this case, the very display of contrition that the film implies Frost had to wrestle out of Nixon:

While the script is straightforward about the fact that under their agreement Nixon was to be paid for the interviews (a then-whopping $600,000), a highly unusual arrangement, it omits the even more questionable part of the deal in which Nixon was guaranteed twenty percent of the profits from the sales of the interviews to television stations. Thus, the two purported gladiators were in business together, with a mutual interest in making the interviews interesting enough to make a nice profit.... To further disguise the degree to which the interview project was essentially a fix, the script of both the play and the movie simply leaves out the episode in which, after Nixon returned to his dressing room during a sudden break in the taping of the Watergate segment - the break misrepresented in the script as having been called for by Nixon aides worried their boss was becoming uncomfortable, whereas it was actually called for by Frost because he misread a cue card held up by the Nixon aides saying "Let him talk" - Nixon aide Jack Brennan (Kevin Bacon) told Frost's frustrated aides, "He knows he has to go further. He's got more to volunteer." These lines appear in neither the play nor the movie.... [Playwright Peter] Morgan himself told John Lahr of the New Yorker after the play came out, "I could just as easily written the piece -- and found substance to support it -- to substantiate it, that Frost didn't get Nixon, that Nixon threw it in, for these interviews to sell."

 Finally she notes that the key sentence of the Nixon's "confession" in the film never actually took place:

[T]hrough a sleight of hand, the script simply changes what Nixon actually said: the script of the play has Nixon admitting that he "...was involved in a 'cover-up,' as you call it." The ellipsis is of course unknown to the audience, and is crucial: What Nixon actually said was, "You're wanting to me to say that I participated in an illegal cover-up. No!"

The whole thing is very much worth reading. 

--Christopher Orr