Ostensibly, the new gangster drama “Public Enemies” is about the famed Midwestern bank robber of the 1930s, John Dillinger.

In fact, it’s all about Johnny Depp (“Sweeney Todd: The Demon Barber of Fleet Street”). His star power is the driving force that makes this handsomely mounted but emotionally barren tale as entertaining as it is.

Director Michael Mann (“MiamiVice”) and co-screenwriters Ronan Bennet (“Lucky Break”) and Ann Biderman (“Primal Fear”) based their film on Bryan Burrough’s nonfiction tome “Public Enemies: America’s Greatest Crime Wave and the
Birth of the FBI, 1933-34.”

No wonder it feels a bit more like a History Channel documentary than it does a Hollywood movie.

But the charismatic Depp gives it the Tinseltown aura. Mann’s camera loves him, and his personal magnetism turns Dillinger into a nearly heroic figure instead of the amoral criminal that he undoubtedly was.

The film focuses not only on Dillinger, but also on the federal agents who relentlessly pursued him. This secondary and far less compelling storyline involves famed FBI Agent Melvin Purvis (Christian Bale from “Terminator: Salvation”), a driven G-man with personal demons that this film only hints at.

Bale is a formidable actor and dynamic force in his right, but he barely registers in a role that seems to have forced him into a dreary box. It is a testament to Depp’s appeal that Bale
seems to fade into the background.

Although the film is filled with colorful and infamous characters (Baby Face Nelson, Pretty Boy Floyd, Frank Nitti, etc.) they’re little more than background noise here. Billy Crudup(“Watchmen”) manages, however, to create some sparks in
his few scenes as the petulant J. Edgar Hoover.

But the only other truly compelling character who emerges in “Public Enemies” is Dillinger’s sweetheart, coat-check girl Billie Frechette, beautifully played by Oscar-winning actress Marion Cotillard (“La Vie En Rose”).

Indeed, it is the love story that provides the heart of the picture and gives the audience a reason to root for Dillinger, a man with a bleak aesthetic and live-for-today credo.

The solid production design helps Mann capture the Depression-era feel and the cinematographer Dante Spinotti, who also shot Man’s memorable thriller “Heat”, uses handheld cameras
in a creative way to generate a sense of immediacy.

But “Public Enemies” has a somewhat routine matter-of-factness about it. In terms of the gangster genre, it adds nothing new.

But Depp saves the day. “Public Enemies” is the quintessential star
vehicle for an actor who seems to
have it all. (R) Rating: ***

* Avoid at all costs

** Only if you're bored

*** Good movie

**** Well worth your time

***** Be sure to see it