And sometimes Sayles approaches questions of history at a rather more oblique angle. His latest film, Lone Star, already welcomed in the United States as one of the best of a career that has long since earned the adjective "distinguished", is essentially a detective story. But there's a lot more thematic beef on those old genre bones than you might expect. In the man's own words: "The main story of Lone Star is about the sheriff of this small Mexican-American town on the Texas border who is investigating a murder committed 37 years earlier, and the prime suspect is his own father, who was also sheriff of the town and kind of a local legend, beloved by all. So he's having to deal with the legacy of his father, and he's kind of torn, he kind of wants his father to have been guilty of this murder. And it also gets in to the whole strange history of the border, and that legacy of history between the Anglos and the Hispanics. You know, this story could just as easily have been set in Yugoslavia and been about a guy who says, `OK, just because I'm a Croat does that mean I have to hate this guy across the street because he's a Serb?' and, `Is there any way for us to escape that?' "
Surprisingly, given Sayles's unillusioned view of the degree of resentment and suspicion with which America's races confront each other, the general drift of Lone Star is that history can be a nightmare from which it is possible to wake. One of its most telling scenes is a debate among angry parents about the revisionist (ie PC) accounts of Texan history that are being taught in the local school. That argument is left unresolved, and the anger it unleashes is never far from the plot; yet the film's last line, spoken between lovers, is a tentatively optimistic inversion of one of the most famous incitements to an undying grudge: "Forget the Alamo." Hollywood isn't too bad at stories about men and women finding romantic love, but when was the last time you saw a thriller about achieving common decency?
As with his other features, Lone Star offers a number of clues to its director's character. While he may once have played a preacher on screen, Sayles's deepest instincts are those of the storyteller rather than the evangelist, and Lone Star in particular spills over with enough characters, plots, sub-plots and narrative loops and spirals to fill a three-volume Victorian novel. Indeed, Sayles began his career as a prize-winning fiction writer, making his way into the film business by grinding out scripts for Roger Corman, the benign master of schlock: early entries in Sayles's screenwriting CV include such lurid titles as Piranha, Alligator, The Howling and Clan of the Cave Bear.
Now in his later forties, Sayles is a shrewd, garrulous, immoderately well-informed man, with a tall, still somewhat gangling frame and a dress sense - ratty old work-shirts and baggy, label-free jeans - as incorrigibly unfashionable as his ethical preoccupations. And Hollywood - which doesn't have a lot of time for Sayles as a director with scarily unorthodox politics (the rumour runs that one leading producer, asked to consider him for a directing job, screamed: "John Sayles does not exist!") - still has enough horse sense to continue acknowledging his craftsmanship as a writer: he is called on so regularly as a script doctor that you may well have encountered his work without knowing it. For example, he wrote the entire last draft of Apollo 13, though the Writers' Guild of America refused him a screen credit. "The habit in Hollywood is to have serial writers, to use them a bit like toilet paper, and very rarely does a writer who comes in late on a project have a mandate to make basic changes, especially when the screenplay is based on a book. I mean, I wasn't going to have the astronauts crash into another spaceship or be eaten by aliens. But your claim to a screen credit isn't based on whether you make it better, but on the percentage of the script you can prove you've changed. So if you make it 40 per cent worse you're going to get a credit, but if you make it 10 per cent better you're not."
Sayles isn't particularly worried, though, by Hollywood's high-handed way with him. For one thing, he prefers the creative freedom he's managed to slice out for himself in the independent sector - a now-thriving territory in which he was one of the pioneers, making his debut, Return of the Secaucus Seven (1980), for less than the amount most movie stars spend on their wedding videos. "Most of the things Hollywood makes aren't things I would want to spend a year of my life doing. I'm really not interested in being an employee as a director, I want to be in charge and tell the story I want to tell. Whereas if you're working for a studio, unless you had a $100m hit the last time out, you're really at the mercy of who's hot and who's not as far as casting is concerned, and also of market testing, which means you end up re-cutting your movie according to what a bunch of people in Baltimore said on their little test cards."
He recognises, too, that the audience for the kind of stories he tells isn't reliably large enough for him to be confident of recouping even modest budgets. "Roan Inish was a big success for us, relatively speaking, because in the cities where the distributor managed to get it screened, word of mouth soon got out and we got runs of 15, 20, even 30 weeks. So there is that little part of the ecosystem you can sneak into once in a while. It's really, really hard to get into the chain theatres, however, so there are whole states we have never played. You're gonna play South Carolina on video, because there's just not a place that shows non-Hollywood movies, and in Wyoming you won't even be able to get the video except by mail order."
Tightly as Hollywood may control the means of distribution, however, it is the unwitting patron of Sayles's productions. Since he is often a principal investor in his own films - "With something like Passion Fish, to make it for the low budget we did I really didn't pay myself anything as a director or editor, and just gave myself scale as a writer" - the only way he can keep going in the business is as "a writer for hire". This has its benefits in keeping him disciplined as a director: "I know that if I go over-budget I have to go and write three movies for other people." The disadvantage is that it keeps him working at a rate which would pole-axe less energetic scribblers. Between January and April of this year alone, he wrote half a dozen scripts, putting each one through three or four drafts. "Writer's block is really not an option for me," he remarks drily.
Indeed not. Apart from his three novels, a short-story collection, several television series, an instructional book on directing and the odd piece for stage, Sayles has now written well over 50 screenplays, including the script for his next film as director, a political thriller which will be set in Latin America, and filmed entirely in Spanish and Mayan. The title? "Men with Guns - in Spanish, Hombres Armados. It occurred to me that about half the films ever made could be called that, so why not just take that title?" Sayles may never be able to outshoot the studio's big cannons at the box office, but he's fighting some of the most worthwhile skirmishes in American cinema.
`Lone Star' (15) opens on Friday.