In what is probably his best work, Heat, director Michael Mann turned a typical cops-and-robbers scenario into a war epic. The criminals led by Robert De Niro and the detectives commanded by Al Pacino were merely combatants positioned by fate and economics on opposing sides. The movie gave us permission to admire coolness under fire no matter who displayed it. And if innocent bystanders got caught in the crossfire, well, that was merely a cruel fact of warfare. Should a psychopathic criminal wreak unnecessary havoc, then mastermind De Niro would execute him, like a good general shooting a looter. He and Pacino saluted each other across enemy lines while respectfully, regretfully, seeking each other's destruction.

Whatever moral qualms this approach might have aroused, Heat was gripping. Depicting the personal lives of his antagonists, Mann didn't just reinforce the banal truth that outlaws are human, too, but concretely dramatized the many ways—health, aging, sex, finance, parenting—in which life harasses the moral and the immoral alike. And since the director lucidly filmed the violence, we could have the Olympian satisfaction of spotting just where a heist or an arrest went haywire.

But Mann's latest crime epic misfires. Portraying the final months in the career of John Dillinger and his destruction at the hands of FBI agent Melvin Purvis, Public Enemies relies on sheer noise and the blur of fast movement to create excitement instead of careful choreography and the creation of interesting characters. Dante Spinotti's high-definition photography has been praised even by critics left otherwise cold, yet the camerawork is a major factor in the film's failure. So much gunfire spurting out of velvety shadows, so many cars careening over forest roads painted by silvery moonlight, so many bodies encased in thick overcoats tumbling down dingy staircases in ill-lit corridors! What sweeping pans, what dramatic zooms, what artfully jagged editing! But who were those tumbling corpses? From what direction were the lawmen approaching? In what direction were the hoods retreating? What was the FBI master plan for tracking the criminals? What was Dillinger's escape strategy? Or are we not supposed to care about such things, but simply to submit to the mindless exhilaration of machine-gun fire and the squeal of brakes? To compare the bank robbery gone wrong in Heat or the attempted arrest in the nightclub in Collateral with the various firefights in this movie is to see the difference between chaos clearly filmed and chaos in the moviemaking process itself.

The script (by Mann in collaboration with Ann Biderman and Ronan Bennett) is straightforward enough about what the two male leads represent. Dillinger (Johnny Depp) is the outlaw as super-individualist, while Melvin Purvis (Christian Bale), though courageous and nobly devoted to duty, is a company man whose crime fighting supports the rise of J. Edgar Hoover, portrayed here (in an expert performance by Billy Crudup) as a prissy protofascist. But for these antagonists to come alive in more than a schematic way, we would need to see them interact with believable characters. Unfortunately, the gangsters and the G-men in the supporting cast are stick figures. For instance, the role of Baby Face Nelson is filled by a baby-faced actor who screams a lot, but that's not enough to make him a fascinating psychopath. The other robbers are simply indistinguishable from one another.

So are Purvis's confederates. Finding the college-educated staff that Hoover assigned him inadequate, Purvis brings on board some tough lawmen from Texas and Arizona. But what precisely did they contribute that the college guys could not? Greater brutality? Fewer scruples? Shrewd insights into the criminal mind? An ability to read road maps faster? The movie just goes blank here. In the final scenes, Stephen Lang brings an unforgettably icy stare and a potent presence to the role of the detective who finally dispatches Dillinger, but his role emerges too late in the story to take hold of us. Likewise, who were the two women with Dillinger when he was killed? We are shown that the Romanian Anna Sage was being blackmailed by the FBI into fingering the criminal, but why was she with Dillinger in the first place? And why was a much younger woman, Polly Hamilton, traveling with them? Who was sleeping with whom, if sex was indeed involved? Were all these characterizations left on the cutting-room floor? Is the real Public Enemies going to emerge on DVD in a four-hour version? (I find myself asking this question more and more often as I encounter more and more big-studio releases with gaping holes in the plot.)

What makes this movie's failure especially regrettable is the fact that the three leads are well played. Depp gives Dillinger the saturnine mask we've all seen in newsreels and photos but also keeps us aware of the crosscurrents of violence, decency, humor, and itchiness at play beneath the mask. As the hat-check girl who becomes his lover, Marion Cotillard (who won an Oscar for her role as Edith Piaf in La Vie en Rose) was stuck with the script's worst dialogue and a lame backstory, but her face provides enough humanity to distract us from the clichés. Underpraised by most reviewers, Bale actually gives the best performance of all, for his acting supplies a background for Purvis that is missing from the script. From the moment he utters his first lines in a gentlemanly Southern accent, Bale establishes the young agent as a well-brought-up country boy determined to make good in the big city. His stiffness of carriage and clipped manner are not the marks of a hypocrite or a prig but the economies of a man who loathes disorder and believes that an energetic devotion to duty and rules ensures success.

The last twenty minutes of Public Enemies are remarkable. His confederates all dead, his career pretty much finished, a living legend at loose ends, Dillinger wanders through a Chicago neighborhood and accompanies Polly Hamilton into a police station where she has some minor business to clear up. There, the bank robber casually saunters into the very room where an anti-Dillinger division is quartered. Listening to a baseball broadcast, the detectives take no notice of their quarry. Having cut himself off from the law-abiding masses, Dillinger has become a kind of ghost. (I was reminded of Nathaniel Hawthorne's Wakefield.) If only Michael Mann had made a quiet, eerie 90-minute movie about the last hours of Dillinger instead of this bloated 140-minute barrage of bullets—too exquisitely photographed for its own good, too lacking in the meaty characterizations that would have made us care about what happens between the bloodbaths.