By ELEANOR RINGEL GILLESPIE
Cox News Service

Like Denzel Washington's "Training Day," with which it shares a screenwriter, David Ayer, "Dark Blue" is less a terrific movie overall than it is a terrific showcase for a longtime actor. In this case, it's Kurt Russell, who gives a shatteringly smart and out-there performance as a crooked LAPD cop.

The film is based on James Ellroy's first screenplay, which set the story in 1965 during the Watts riots. After the script kicked around for several years, Ellroy updated it to 1992 and the Los Angeles riots after the Rodney King verdict. The switch works perfectly, since the movie uses the riots essentially as a compelling backdrop for an action-filled character study.

It's four days before the cops caught beating King will either be convicted or acquitted, and the entire city feels like a powder keg. Eldon Perry (Russell) is the kind of cop who would've had his nightstick out first. Cool, vicious and not above bending the law when it suits him (read, always), he's tight with his corrupt boss, Jack Van Meter (Brendan Gleeson), the beefy, red-faced embodiment of a cop gone bad. When Van Meter wants something done -- especially something dirty -- Perry is his go-to guy.

There's been a robbery-quadruple homicide in a liquor store in South Central L.A. Van Meter wants Perry not to catch the scum who did it (one is rapper Kurupt), but some other scum. That's fine with Perry, who thinks one piece of scum is as bad as another. But there's something dicey about this case, enough to put Perry on alert.

"Dark Blue" doesn't have the texture and weight of another Ellroy policer, "L.A. Confidential." The plot is less complicated, and director Ron Shelton ("Bull Durham," "Cobb") doesn't always trust his audience, i.e., he can be too obvious. But he knows how to put a movie together, and this one gallops along, with double-crosses turning into triple-crosses and every bad cop for himself. It all comes to a head when the not-guilty verdict is announced and South Central explodes (at which point Shelton makes good use of real footage).

There's an awful Big Speech at the end that works only because Russell makes it work, as well as some truly terrible scenes with his ignored wife (Lolita Davidovich, good in a stink-bomb role). But in general, Shelton gets a lot right: the private boys' club nature of Van Meter's office, where he and his cronies sit around sharing scotch and cigars. Or the South Central looter's eclectic tastes: everything from couches and TVs to stuffed animals and jumbo bags of Chee-tos.

But Russell is the reason to see the movie. Like Dennis Quaid, he's creating an entire second act for his career. Perry is utterly repugnant, and Russell plays him with a strutting self-confidence that's as hypnotic as it is detestable. Full of bragging rights and swagger, he's the guy who knows it all -- until he learns he doesn't.