Early historical dramas such as D. W. Griffiths' Abraham Lincoln (1930) and The President's Lady (1953) lent classical dignity to real presidents by casting actors such as Walter Huston and Charlton Heston. Attitudes have become less reverential since then. In 1964 the maniacally talented Peter Sellers played the role in Dr Strangelove and 15 years later appeared as a naif on the brink of presidency in Being There. Kevin Kline played a similarly dim puppet more recently in the satire Dave, while Tim Robbins was a baby-faced monster in Bob Roberts.
Casting depends, of course, on the nature of the film, but if the part is to be more than sitting in a winged armchair with your back to the camera, agents must think very carefully about who they choose.
It seems no coincidence that Anthony Hopkins, with the double credentials of being English and Hannibal Lecter, should be cast in the villainous role of Nixon in the Oliver Stone biopic.
While Michael Douglas may have had the right square jaw for The American President, with Fatal Attraction and Basic Instinct behind him, was he really the right man to play a dishy widower gently dating Annette Bening? Always iconic, the presidency occasionally approaches the sacred. It's hard to think of an actor with enough liberal integrity and sex appeal to play Kennedy, which means that he is usually played by himself in old footage (JFK, Forrest Gump). But perhaps Bill Paxton's youthful, hands-on hero in Independence Day might point to a kind of sci-fi, throwback nostalgia.
So with the Travolta/Clinton casting have we reached new levels of cynicism? After all this is the teenage thug of Carrie, the man who boogied his way through Saturday Night Fever and has made a comeback playing boyish sharks.
All of which makes him the perfect dough-featured, slightly sleazy charmer for the part. Far more pernicious was the vote that put ageing film star Ronnie Reagan in the White House. A piece of miscasting if ever there was.