Even at the age of 81, Clint Eastwood shows no signs of slowing down. He’s directed five films in the past three years. His new film, “J. Edgar,” is a biopic of J. Edgar Hoover, the first Director of the FBI. The film calls to the mind the old Nietzscheanism saying, “Absolute power corrupts absolutely.” “J. Edgar” stars Leonardo DiCaprio as Hoover, a man so consumed by his own demons that he let greatness slip through his fingers.

For 37 years, Hoover was America’s top cop. He arrested gangsters and bank robbers, rounded up suspected Communists, and kept taps on every political figure, including presidents. His time as FBI Director was long and controversial. He often bent the rules in order to effectively enforce the law. He also marketed the FBI along with running it. He oversaw radio serials, comic book series and Hollywood movies, trying to paint the FBI as a heroic band of college-educated G-men. But what was myth and what was reality?

Eastwood and screenwriter Dustin Lance Black have crafted a story reminiscent of “Citizen Kane.” The aged J. Edgar, a stunning piece of prosthetic make-up work by artists Sian Grigg and Duncan Jarman, looks back on his rise to power. The transitions between past and present are fluid. Eastwood never bores the audience, or weighs the film down with exposition. Each scene is well-written, shot and acted, yet it feels like there’s something missing. In “Citizen Kane,” the main character had his “Rosebud”, some key or secret into his psyche. The film’s largest flaw is its lack of a similar device.

The film presents Hoover as a driven and obsessive man. He is lonely and socially awkward, with a domineering mother, played by Judi Dench, and a sick father. Yet no reason is ever given for the way Hoover is. Why is Hoover so obsessed with fighting “Bolsheviks?” What lays behind the bitter enmity between him and the Kennedys? Was it racism that drove him to wiretap and blackmail Martin Luther King or something else? The film never answers these questions. Instead, it provides an engrossing glimpse into what J. Edgar Hoover was like, but no reasons for  why he was like that, thus  keeping “J. Edgar” from being a truly great film.

But it is still a good film. DiCaprio is excellent in the lead role. If he doesn’t receive an Oscar nomination, it will be very surprising. He’s playing a real person in a true story, a guarantee for awards attention. Yet DiCaprio isn’t on acting autopilot in “J. Edgar.” He transforms himself into Hoover, adopting a different voice and look. Hoover didn’t look like a movie star, and it never feels like a movie star is playing him. DiCaprio makes us sympathize and pity Hoover, even at his worst.

Another standout performance is Armie Hammer as Clyde Tolson, Hoover’s deputy and lifelong companion. Hammer plays Tolson as Hoover’s conscience. Hoover can keep secrets, shred files and lie to Congress as much as he wants, but he can’t fool Tolson. Their relationship is often sweet, a surprising touch in a historical drama like this. They pride themselves of having a meal together every day, no matter what else happens.

For years, rumors abounded that Tolson and Hoover were lovers. They were inseparable, often vacationing together and remained bachelors. The film portrays their relationship as one of pure love, not a sexual one. Dustin Lance Black’s screenplay seems to be an attempt to dispel the image of Hoover as a cross-dressing homosexual. It isn’t his possible homosexuality that made him flawed; it was his paranoia and lust for power.

Despite its narrative and thematic missteps, “J. Edgar” remains a good film. It offers further proof that Eastwood is one of the greatest living directors, even after 50 years in the business. And it tells a compelling story with smart dialogue and solid performances.

Danny Marchant can be reached at [email protected]