The ugly American of the novel is an honest, homely engineer, here a minor figure (Pat Hingle, Commissioner Gordon in the Burton-Schumacher Batman films) who runs a rural clinic with his wife (Jocelyn Brando, Marlon's sister). In an unlikely scene, villagers form a human chain around the clinic to protect the couple from the murderous communists who have infiltrated and commandeered Deong's revolution. Of course, the term 'ugly American' has come to be identified with an ugliness of attitude rather than person, exemplified by jovial, know-nothing dolt Joe Bing (Judson Pratt) who replaces MacWilliams as Ambassador after the 'failure' of his mission. Kukrit Pramoj, later the actual Prime Minister of Thailand, plays the Prime Minister of Sarkhan, a pro-American with his hand out who comes on like the unpopular tinpots successive US regimes have supported in all corners of the globe.

A key theme of the book is that Soviet diplomats and agitators have a major advantage because they all learn the local language, while Anglophone Americans abroad live in wealthy enclaves and hire servants -- this, of course, is dropped in a movie which requires almost everyone to talk English all the time. Okuda, a hot name after Hiroshima, Mon Amour, is crippled by having to perform in an uncongenial tongue, though Brando -- in a role which might contextualise his reading of Colonel Kurtz in Apocalypse Now -- see-saws between toffee-nosed twittery and powerhouse speech-making.

It ends with another cartoonish moment, which is admittedly effective -- cutting away to a bland, affluent American living room as MacWhite delivers an impassioned speech about why America is losing the war of ideas and a bored representative Yank switching the television off. Made before the Kennedy assassination (prefigured by a climax in which Deong's supposed best disciple murders him so the communists can completely co-opt his nationalist movement) and US escalation in Vietnam (the Sarkhanese PM cannily ensnares MacWilliams into committing the US fleet lying off his country), this is for all its awkwardnesses a brave film. A few years later, it would have been impossible to make: in 1965, Lederer and Burdick published a sequel, Sarkhan, in which the country slides further into a Vietnam-like war; Lederer reports Hollywood bidding for the rights 'stopped abruptly when Washington hinted that if this novel were made into a motion picture, the industry might find it difficult to obtain export licenses.'

Of course, such measures weren't necessary -- like the modern audiences who preferred to see Transformers or Iron Man over In the Valley of Elah or Charlie Wilson's War, 1963 crowds followed that middle-American TV viewer by not making The Ugly American a hit. Even if it had outgrossed The Great Escape or Move Over, Darling, it probably wouldn't have influenced Washington or affected the outcome of the Vietnam War -- but the movie still earns a few plaudits for seeing the way the wind was blowing.