The Old West died hard in the City of Angels. And in the years after World War II, battle-hardened veterans came home to a town “under enemy occupation,” when the only way to fight off The Mob was with a sixgun, your two fists and the right hat.

“Gangster Squad” is a gang war drama built on Western conventions, a rootin’ tootin’, Camel-smokin’, whiskey swillin’ shoot’em up about a lawless period in L.A.’s history when a small cadre of cops, working outside the law, took on mob boss Mickey Cohen in a fight for “the soul of Los Angeles.”

Josh Brolin ably takes on the John Wayne role, the paragon of virtue, an incorruptible police sergeant  tasked by the only police chief (Nick Nolte) NOT on the take to chase mob boss Mickey Cohen (Sean Penn, ferocious) out.

Ryan Gosling’s Jerry Waters, the cynical detective/gunslinger who will have to take sides, but is going to take some convincing.

“Sarge, the whole town’s under water, and you’re grabbing a bucket, when you should be wearing a swimsuit.”

Anthony Mackie’s the knife-throwing street cop from the black side of town. Robert Patrick is the aged pistolero and holdover from the “real Wild West.” Michael Pena represents the city’s Hispanic underclass, a kid who needs to prove himself. And Giovanni Ribisi is “the brains,” the cop with the glasses and the Army-based knowledge of electronics and wiretaps.

“Who’s the tomato?”

That would be Emma Stone, playing the “dance hall girl,” the mobster’s young moll “poached” by the handsome Jerry.

“Zombieland” director Ruben Fleischer may not do much with this pictorially that suggests “Western,” but he keeps the characters iconic, the morality straightforward and the action clean. Will Beall’s script is peppered with character “types” – gunsels with scars and World War II vintage machine guns. Of course Jon Polito shows up, as he has in every gangster period piece since “Miller’s Crossing.” And Beall’s dialogue gives “Gangster Squad” an extra kick.

Insults — “He’s got a smart mouth, but he’s dumb where it counts.”

Compliments — “Push comes to shove, kid’ll stay behind his gun.”

This “inspired by a true story” tale bears more than a passing resemblance to an earlier Nolte fedoras-and-fistfights cop picture, “Mulholland Falls,” named for a hillside where brutal cops sent gangsters tumbling after one of their “Get outta town” lectures. Brolin & Co. even pay a visit there.

But the real connection here is to Westerns — especially “The Magnificent Seven,” a “Magnificent Six” in this case, right down to Mackie’s character’s choice of weapon — James Coburn’s knife.

All in all, “Gangster Squad” is a solid piece of work, and that solid piece of work Brolin anchors it in the kind of square-jawed moral rectitude that makes you wish Hollywood made more REAL Westerns, just for him. He’s fine in a trenchcoat and fedora. But somebody get that man a horse.

MPAA Rating: R for strong violence and language

Cast: Sean Penn, Ryan Gosling, Emma Stone, Josh Brolin, Anthony Mackie, Robert Patrick

Credits: Directed by Ruben Fleischer, written by Will Beall, based on the Paul Lieberman book.  A  Warner Brothers release.  

Running time: 1:50