“Nail ’em up. Nail ’em up! You give me the hammer and I’ll do it.” So goes the battle cry of one Willie Stark, the self-made man based on Huey Long in Steven Zaillian’s new film, All the King’s Men. As played by Sean Penn, Stark teeters on the edge of insanity, always soused but rarely drunk, concerned for the masses but forgetful of their true needs, angered by the fat cats at the state house but willing to take a piece of the pie for himself. Penn makes the most of the role; with mussed hair and contorted face, he is a sight to behold as he plays a political game for which he has no qualifications other than a mean temper and a healthy set of pipes.

Yet, despite the fame and talent of his castmates, Penn seems alone in his passion. Generally reliable actors such as Jude Law, Kate Winslet, Anthony Hopkins, and Mark Ruffalo fill out the roster without giving their roles a fraction of the energy or nuance we have come to expect from them. Winslet and Hopkins sometimes feel only halfway involved. Ruffalo is miscast as a genuine do-gooder; his presence is better suited for the other side of the tracks, as he so capably demonstrated in Kenneth Lonergan’s superior You Can Count on Me. And Law, well, he is just plain in over his head.

As he attempts a Southern drawl, he sounds like a Brit trying to fake American, not yet aware that there are multiple dialects on this side of the pond. Law, playing a reporter who joins Stark’s political team as they take on Louisiana state politics in the 1950s, is not terribly convincing in any aspect of the portrayal, especially when he is called upon to act in the presence of the hammy Penn. No doubt Willie Stark is intended to be a character that upstages the others, but the comparison is so drastic as to make the non-Penn players feel unnecessary to the film’s dramatic progress. Law’s career has been peppered with really good work, probably none better than his role as golden-god playboy Dickie Greenleaf in the oft-overlooked The Talented Mr. Ripley. But, hey, Jude, you are not an actor who can just wander into any role and be convincing. You have a type and All the King’s Men does not allow for it.

Perhaps that is what the film turns out to be: a story of how even wonderful actors cannot atone for fatal errors in the casting and screenwriting departments. Only Patricia Clarkson and James Gandolfini seem to have landed on their feet, mostly because they play their strengths as a woman who understands more than she says while smiling and a tough guy, respectively. Otherwise, though, the final cut feels more like an early rehearsal, complete with slips and slides.

The plot itself is interesting enough. Something really good could be done with the premise. Many would argue that some really good things have already been done with it, as in Robert Penn Warren’s book or the 1950 film. This version is an adaptation of the former, not the latter, but the three follow the same basic story arc. Willie Stark rises to minor public repute when he tries to blow the whistle on the construction of an overpriced, shoddy school. After three children die in a fire at the site, Stark gains brief credibility and is fronted as a candidate for governor, unwittingly serving to divide party votes and keep the oil industry in power. But Stark is no pushover, and he wins by a landslide, in large part because he is willing to insult anyone, promise the utopia of socialism to everyone, and, most importantly, remain idealistic and cocky even as he is revealed to be an ill-mannered, uninformed leader.

Other characters float in and out of the picture, but they remain fuzzy. Ruffalo’s character, for instance, is a doctor who agrees to be used by Stark because he sees the greater good of building a public hospital, even if by somewhat dishonest means. But when the story calls on the good doctor to play a pivotal role in the outcome of Stark’s career, his intrusion seems unwarranted and Ruffalo, for all his efforts, wasn’t really given the chance to make the sudden plot twist seem believable from his end. All the King’s Men is, from beginning to end, Penn’s show, and to that extent it achieves mild success in spotlighting an interesting character acted with panache. But everything else is left anemic. The musical score tries to compete, utilizing big bangs of sentimentality mixed in with action-movie histrionics. The prop design perks up with what can only be described as a flashbulb fetish, hoping to draw up some attention to the masses of reporters surrounding Stark at every turn. But these attempts are futile. All the King’s Men is off-balance. This is a one-man-show where Penn is surrounded by a lot of unnecessary extras. “You give me the hammer and I’ll do it,” he says.