2. Nixon
Aside from top-hat and beard wearing Abraham Lincoln, President Richard Nixon is probably the single most recognisable face to have ever reigned supreme in the White House. Thanks to his Walter Matthau-like hanging jowls, the seemingly perpetual frown and the high hair-line, he had the sort of visual markers that would make any attempt to caricature him a simple enough prospect - nail those three key things and the rest would be easy. Sadly, Oliver Stone was clearly less inclined to believe as much, and he didn't spend nearly as much time as he could instructing his production team to make the physical transformation equal to Hitchcock's performance as the President, which is a shame considering how much co-star Joan Allen looks like Pat Nixon.
How He Really Looked
Hopkins' Version A grumpy expression does not a Nixon performance make, and though it was a long time ago, the advances in prosthetics well before the release of Nixon would have been more than adequate to allow Hopkins at least some of Nixon's iconic saggy jowl. To be perfectly honest, Hopkins could have merely "done a Brando" and stuffed his jawline with some dental cotton wool or something to give the impression of size, though clearly that would have come at some cost to his performance. It just seems like something of an oversight to try and capture Nixon's haircut, his perpetually melancholic expression and his mannerisms, and not do something to make the star's face resemble the former President's own instantly recognisable visage.