O brothers, what hath thou wrought?

Expectations to the contrary, Joel Coen is “not an indiscriminate fan of violent films.” He and his brother Ethan may have made some legendarily ferocious films, including the likes of “Fargo” and “Blood Simple,” but, Joel says, “there are certain violent ones I see the previews for and I say, ‘I don’t want to go.’ ”

The Coens, sitting side by side in the noticeably peaceful lobby of the Hotel du Cap, are in competition at the Festival de Cannes with yet another violent film, their adaptation of Cormac McCarthy’s “No Country for Old Men.” Yet there is something different about this one, so much so that the brothers, who share writing, directing and producing credit, say they would consider letting their oldest children, not quite teenagers, see it. “They could both watch this,” Joel says, “and take it in the right way.”

That’s because there is on-screen violence and on-screen violence, and “No Country for Old Men,” the story of stolen drug money and the carnage it precipitates, is a film that doesn’t celebrate violence, it despairs of it. This is a completely gripping nihilistic thriller, a model of impeccably constructed, implacable storytelling. All you could hope for in a marriage of the Coen brothers and McCarthy, it’s a film that you can’t stop watching, even though you very much wish you could as it escorts you through a world so horrifically bleak “you put your soul at hazard,” as one character says, to be part of it.

One of the things that makes “No Country” different, the brothers agree, is that pitiless quality. “That’s a hallmark of the book, which has an unforgiving landscape and characters but is also about finding some kind of beauty without being sentimental,” says Ethan. There is, adds Joel, “no sort of relief from the unrelenting nature of the story.”

It was producer Scott Rudin who bought the book rights and offered it to the Coens, who at the time were working on a project that fell apart, an adaptation of James Dickey’s “To the White Sea,” a novel about the firebombing of Tokyo that the brothers say had a similar violent theme.

With this adaptation, the Coens have stuck remarkably close to the book, doing more pruning than anything else. “We weren’t going to rewrite Cormac McCarthy in any substantial way,” says Joel, while Ethan, dealing with the common misunderstanding of what’s involved in adaptation, adds a mocking, “It’s work to hold the spine open so you can copy the words.”

One of the places in where the Coens found common ground with McCarthy was in the novel’s tendency to fool around with genre conventions. “That was familiar, congenial to us; we’re naturally attracted to subverting genre,” says Joel. “We liked the fact that the bad guys never really meet the good guys, that McCarthy did not follow through on formula expectations.”

Another area that attracted the Coens was the novel’s intense sense of place. “The regional thing is strong for us, and this was not East Texas or South Texas, this was West Texas,” says Ethan. The Coens and their regular cinematographer, Roger Deakins, shot key exteriors in that part of the state. “We turned over the idea of shooting exclusively in New Mexico, where there are great tax incentives, but Tommy Lee Jones, who comes out of that West Texas landscape, yelled at us that it would be a mistake,” says Ethan. “So it wasn’t all principle, it was partially browbeating.”

Jones, who plays disillusioned Sheriff Ed Tom Bell, was the first person cast in the film. “It was an easy decision, but not an automatic one,” says Ethan, and Joel elaborates: “You’re sort of aware you don’t want to be too much on the nose with casting, but it’s not exactly like you’d read the book and think Tommy Lee embodied the character exactly. Tommy Lee brings acid to him that isn’t in the book, and that was kind of interesting to us.” Ethan adds, “We had a horror of sentimentality; we didn’t want Grandpa Charlie Weaver.”

The next to be cast was Javier Bardem, who plays the golem-like contract killer of mysterious ethnicity, Anton Chigurh. “We wanted somebody who could have come from Mars; we even shot the beginning of the film like ‘The Man Who Fell to Earth,’ ” says Joel. Given that the story takes place in the Southwest, the Coens worried briefly that Bardem’s Spanish ethnicity might make him too tied to place, but Bardem’s gifts won them over.

But because “No Country” is what Joel calls “a three-headed monster,” the Coens still needed to find the third lead, a local named Llewlyn Moss who takes the drug money. “Having cast these two guys,” explains Ethan, “we didn’t want to cut to ‘Here’s the dull guy.’ We were like, ‘Oh God, what are we going to do?’ ”

Fortunately, just before shooting started, the Coens found Josh Brolin as Llewlyn. The major surprise of the film, Brolin, who grew up on a ranch in Central California, easily holds his own with his costars, bringing the kind of grounded rural presence to the role the brothers considered essential. “We lucked out with the casting,” says Ethan. No one who survives this disturbing, unsettling film will be in any mood to argue.

kenneth.turan@latimes.com