James Mangold's Cop Land wants to provoke serious discussion about corrupt elements in the police department, yet there's never a clear breakthrough in terms of rooting out the central problems. Cops will stand by one another no matter what the consequences. Where does this leave the larger issue at hand? Probably on a desert island somewhere hoping to be found by someone brave enough to ask the important questions.

Todd Thaler's casting brings together an incredible number of gifted thespians, some of whom have worked together before. Robert De Niro appears alongside his Mean Streets co-star Harvey Keitel and then there's Ray Liotta from Goodfellas. Unfortunately, De Niro and Liotta don't share a single moment of screen time. Other problems which hinder Cop Land are a frustrating lack of urgency and the music score by Howard Shore. The latter pounds away with the orchestra to no effect.

Sylvester Stallone sheds his movie star image, putting on an extra 40Ibs to play Sheriff Freddy Heflin. He's a decent guy, who lives with significant hearing loss in one ear due to an incident in his youth. Throughout the film, Freddy unearths a few secrets about the police force which he has trouble accepting. It takes a great deal of pressing from Internal Affairs officer Moe Tilden (De Niro) to get the ball rolling.

I praise Stallone for having the courage to try something new. However, the film still requires more work in order to iron out a few problems. For example, there are far too many characters put in place for convenience. Annabella Sciorra seems to exist outside the film's parameters. Her fondness for Stallone's character elongates the picture, making it far more laborious as a result.

Momentary jolts are infrequent, yet welcome when they occur. Pacing meanders, especially during act one, where individual loyalties are established and the seeds of dramatic heft are eventually sown.

There are marvellous performances to be found here. Some are extraordinarily well-defined, particularly Liotta's drug addicted cop whose conscience gets the better of him in one life-altering moment. Keitel and Robert Patrick are very good. The former represents a classic approach to screen acting, something which goes back to his experience working with director Martin Scorsese.

The bottom line? Cop Land has its mind in the right place, only its emotional core feels out of sync. Overall, Mangold's layering of various strands as a form of contemporary Greek tragedy misses out on a certain flair for the dramatic.

(Released by Miramax and rated "R" by MPAA.)