Spoiler alert. Read the book (1956) and/or watch the films (1958, 2002) first.
All I remember about my first viewing (some years ago) is being quite confused about why Pyle and Fowler acted strangely in both their relationship with each other and their dealings with Phuong. This confusion ruined my enjoyment of this well crafted film. I watched the movie again today and have a new appreciation for its genius.
Since my first viewing I have walked many of the Saigon streets in the film so the whole movie felt much more familiar. I have also learned a little more Vietnamese history from the 1950s. I have not read Graham Greene's book or seen the 1958 movie. I accept that a 2002 interpretation by an Australia director (Phillip Noyce) made a couple of decades after the Vietnam War will have a different spin. Here is my opinion.
The relationships between the characters are parallels to the global forces they represent. Pyle is the USA, Fowler represents old Europe, Phuong the hope of new Vietnam and her sister the practical cynicism of old Vietnam. Old Man Europe and new Vietnam are happy lovers but old man Europe cannot fully commit to new Vietnam because of prior commitments outside his control. USA offers a marriage to new Vietnam and old Vietnam approves. The sister works directly for the Americans once the marriage between new Vietnam and the USA is arranged.
Phuong's character is never fully developed and this represents the hopeful possibilities of new Vietnam. Her name means Pheonix which is a western symbol for rebirth. She is largely controlled by her sister and we learn that she was the daughter of a professor. Phuong’s background is not one of naiveté. Van Mieu; the Temple of Literature in Hanoi (an old University) is nearly one thousand years old. Phuong’s emotions are either enigmatically blank or joyful - except when she was lied to about a marriage with Old Man Europe. It was no accident she proudly took the letter to her older sister who then told her the truth - this was old and new Vietnam realising it needed new allies.
The scene where Pile proposed to Phuong while Fowler looks on seems crazy. What man would let or encourage another man to propose to his lover? The whole relationship between Fowler and Pyle tolerating each other's affections for Phuong is nuts. How could a man be so forgiving of another for taking his mistress from him? Fowler's agreement that she would have a better life is nothing more than a platitude. This scene (and many others) make no sense until you realise this is America and old man Europe courting the new and hopeful Vietnam.
Bill is the powerless colonial ex-pat. His manners are poor even by his own country's standards but he tolerated in Vietnam provided he spends money. Bill is wrapped up in his own concerns and is oblivious to the world around him. Always drunk. His home country is sick but there is nothing the ex-pat can do. Vietnam is where he feels important.
At the film’s end the new and hopeful Vietnam happily embraces old man Europe and they forge a new future together. I'm told that in the book Fowler finally gets permission to marry Phuong. This is not made obvious in the 2002 movie - which probably reflects the passage of history.
With that lens, The Quiet American starts making sense to me. It is a way of metaphorically communicating a complex history through the familiar mode of a love story.