Relativity: "The Sisters Brothers"

As its title suggests, The Sisters Brothers is principally made up of elements that don't or shouldn't connect up, or which only connect up in peculiar ways. Here is a film-reminder of the fact there was once a time, not so very long ago, when America could legitimately have been described as the Disunited or Estranged States, fumbling its way towards some notional national cohesion. Some will argue that it's not quite there yet. At its centre are a pair of siblings who are deployed by the powers-that-were as hired guns, but who would otherwise appear to have little in common but a surname. The sottish, reckless Charlie Sisters (Joaquin Phoenix) does the majority of the shooting; the more genial Eli (John C. Reilly) is content to hang back, either as a result of his seniority, or his physical bulk. As we join them, they've been pitched up the trail by a Commodore (a spectral Rutger Hauer, glimpsed briefly through a window, heard from not at all) to link up with a dandyish scout (Jake Gyllenhaal, an American trying an English accent) who's been keeping tabs on a rogue prospector with a considerable bounty on his head (Riz Ahmed, a Brit with an American twang). There's something strangely mathematical about the film's formulation: we're watching the working out of simultaneous equations, one involving figures who don't obviously tessellate - you at first struggle to reconcile Phoenix and Reilly as blood brothers - the other two individuals who mesh unexpectedly. The $64,000 question is whether the four of them are about to add up, or will simply cancel one another out.

The end credits will reveal one further incongruity: that The Sisters Brothers has been brought to the screen by Jacques Audiard, the French writer-director behind 2009's A Prophet. (If that's not odd enough, consider the fact a Western produced by Belgium's Dardenne brothers and Romania's Cristian Mungiu is currently holding down Screen 12 at the local megaplex.) We should bear in mind, however, that Audiard is one of those Gallic auteurs who've long displayed an affinity with Americana: it was evident as early as his 1994 gangster movie See How They Fall, and came to full fruition in 2005's The Beat That My Heart Skipped, his nimble Parisian rethink of James Toback's Fingers. What Audiard and regular co-writer Thomas Bidegain may have seen in Patrick DeWitt's source novel was a continuation of a recurring theme in their own work, namely the ways men position themselves in relation (and sometimes opposition) to one another. With Hauer's white-haired Commodore presenting as a predecessor to Niels Arestrup's distant father in The Beat That My Heart Skipped, obliging the younger men to carry out his dirty deeds, the new film establishes a pecking order with notable economy, then watches everybody shuffle up and down it. What keeps the film from the arch eccentricity it threatens to strike out towards is Audiard's patient, classical storytelling. We're always aware of just where these two-by-twos are and who's on who's side at what time, and crucially the director doesn't ever force his disparate narrative elements together in a bid for some commercial gold rush. More Eli than Charlie, Audiard's happy to drop back and observe how far these men will go in pursuit of their goals, to see how and why they fall.

The results prove vastly more even and rewarding than the Coen brothers' recent The Ballad of Buster Scruggs, which felt (to this viewer at least) like a half-dozen stray thoughts scrawled on the back of an envelope and sold on to Netflix at top dollar. Audiard's film has the sly, connoisseurial appeal of a character piece disguised as a linear chase movie: the further we get along the route, the more we get to know, good and bad, about these distinct and distinctive cowpokes. The roles cry out for excellent company above all else, and Audiard has availed himself of at least two of the best American actors currently working. Phoenix and especially Reilly - quietly extraordinary here, even by this actor's own high standards - succeed not just in conjuring a deep-rooted, protective fraternal bond, but in getting us to root for a pair who've earned an entirely justified reputation as cold-blooded killers. Much of that achievement stems from Eli's galumphing openness to new experiences, be that a hotel water closet or the newfangled toothbrush, and the attention he sporadically pays to those small moments of beauty that present themselves amid the discharging of pistols and the thundering of hooves: the wind rustling the treetops, or a curtain flapping in the breeze, the latter a poignant madeleine of an earlier, more domesticated existence. This America hasn't yet fixed or finalised itself, so we see no reason why a relatively cultured fellow like Eli shouldn't put down the gun and live more peaceably; his evident love for Charlie, his sometimes exasperated attempts to keep the kid from doing something mortally stupid, leads us to conclude he might be worth saving, too.

Which is to say The Sisters Brothers is far lighter and gentler in its Darwinism than the often brutal (and pretty chilly) A Prophet, but both films strike me as very much caught up with men confronted by a stark fork in the road: evolve or die. As the one scientist among this party of four (carrying, it transpires, several barrels of misappropriated catalyst) optimistically phrases it: "We'll all change - we don't have any other choice." Audiard, making his own decisive and largely successful mid-career shift, runs up against one obvious visual limitation, perhaps connected to his lowly status as a first-time director in the New World. This is the kind of big, elegiac throwback picture that cries out for the crisp definition of film; it instead gets rather sketchy digital photography, which renders some of the night and (otherwise capably handled) action scenes lamentably smeary. I also wonder whether some viewers will see it as a weakness that - beyond a late and very welcome cameo - Audiard and Bidegain see little place for the fairer sex in this world, although the absence of women allows the men to run the emotional gamut from murderers to nursemaids. Rather than hardened by their experiences out on the range, these brothers come to be softened, opened up one way or another: their final destination is both unexpected, and unexpectedly lovely. It's the kind of odd, angular, melancholy venture you'll likely find ricocheting around inside your head in the weeks between now and HBO's forthcoming Deadwood pay-off - and here, at last, might be the project The Sisters Brothers most readily lines up with: another supremely characterful illustration of the radically different impulses on which modern America was founded.

The Sisters Brothers is now playing in selected cinemas.