Thanks are due to Robert Duvall, whose clout as an actor probably got the American Movie Channel (AMC) interested in presenting its first ever original production with this two-part Western that debuts Sunday night. There may be plenty of quibbles: The story could be stronger, the performances are uneven, cliches abound. But this is an unapologetic romance of the Old West, and quite entertaining on its own terms.

Two of the most enduring genres of Hollywood’s Golden Age – the Western and the musical – have clearly fallen on hard times. The last serious effort at a Western – the estimable “Open Range” in 2003 with Kevin Costner and, again, Robert Duvall – was seen by not more than about 400 people. Movie musicals lately have been making a stuttering comeback, with more misses (“The Producers,” “Rent”) than hits (“Chicago”). Can there be hope for the horse opera?

Serious aficionados should probably not anticipate a renaissance featuring Monument Valley and the great John Ford’s often sentimental but occasionally scalding visions. Still, as “Broken Trail” amply demonstrates, there continues to be promising material here. And, of all the genres, the Western is perhaps most significant for its connection to the history and meaning of America.

Ever since Frederick Jackson Turner in 1893 proclaimed the central importance of the frontier in the formation of the nation, historians have taken the Old West into account in defining American exceptionalism. The frontier shaped American concepts of individualism, the role of the state, private as opposed to public charity, law and order, and what neighbors need to be. Turner’s famous paper, “The advance of the American settlement westward,” was – for him, and many of the scholars who followed – the central story of American history. As he memorably put it, the frontier was “what the Mediterranean Sea was to the Greeks.” And Homer’s “winedark sea” held no more terrors and delights than the prairies and mountains of the West.

The cruelty and suffering, as well as the heroism and altruism, are evident in “Broken Trail,” which follows the misadventures of Print Ritter (Mr. Duvall) and his nephew, Tom Harte (Thomas Haden Church), who are driving a herd of horses to Wyoming.

Along the way they cross paths with a group of young Chinese women who have been sold into prostitution in San Francisco and are being transported to a mining town several hundred miles East. The creep who is transporting the girls ends up raping one of them and robs Ritter and Harte of money and some horses, but Harte soons catches up with him and dispatches him with a makeshift noose. Ritter and Harte recover their goods and set off with the girls for Wyoming, only to find themselves passing through the mining town where the girls were supposed to “work.” There, a hard-bitten brothel owner, unforgivably named “Big Rump” Kate (Rusty Schwimmer), is determined to claim her property. The balance of the story determines the girls’ fate, along with that of a former prostitute, Nola (Greta Scacchi), who seeks protection from Ritter and ends up falling in love with him.

It is fair to say that the customary traditions of the classic Western are honored in “Broken Trail.” Neither hero is particularly articulate with the opposite sex, but both manage to find a love interest. Ritter, like so many cowboys before him, stands at a distance from his society. Evildoers pay a stiff price. The scenery is stunning and the music stirring. The director, Walter Hill, is a veteran action filmmaker who also directed the pilot for “Deadwood” and the hit film “48 Hours.” He keeps the narrative moving smartly and appears to take the material seriously.

The biggest problem with this film, apart from the Madam’s nickname, is the Chinese girls, who are attractive but practically inert throughout the proceedings. When one of them, the rape victim, attempts suicide, you’re more surprised than sorry. All of Mr. Duvall’s formidable skills as an actor are not enough to create chemistry with them. And he tries so hard, and with so much schtick, that it begins to look more like hard work than acting.

There is, on the other hand, ample chemistry between Ritter and Nola and even more between Ritter and his nephew, effectively played by Mr. Church, who made such a mark as the Lothario suffering a mid-life crisis in “Sideways.”

No one who has savored the great Westerns films of the past will rank “Broken Trail” among them. It is hardly art, but for the most part it is honorable entertainment. Mr. Duvall, who also is credited as the executive producer, has done his part to breathe some life into an endangered species.