Sean Penn is probably the finest actor working in Hollywood. His talent is matched by a formidable commitment to whatever role he's been hired to play, which gives him the type of gravitas that Robert De Niro and Dustin Hoffman used to possess before they began selling their talents to the highest bidder. But lately many of Penn's films have seemed like showcases for his acting chops. Certainly, the films themselves have all been worthy projects. Yet one walks away with little else than the emotional brows and explosive vocal cadences of the star.

I Am Sam from 2002, where Penn played a mentally disabled man seeking custody of his daughter, is perhaps the foundation for this trend, which continues with the The Assassination of Richard Nixon.

Penn plays would-be assassin Sam Bicke, a real-life figure who attempted to hijack an airplane to crash into the White House at the height of the Watergate scandal. Bicke is one of America's great losers, one of those luck-soured souls who cannot survive in America's social Darwinist landscape. "Slavery never really ended in this country," he says at one point. "It just gave it another name: employee."

Bicke has always scraped by, accepting dead-end jobs that reduce existence to a time-clock-to-tavern routine. Yet he's also been infected with the American Dream, and carries the delusion that he's close to becoming a great success as a small businessman. In the meantime, he's found a job hawking office furniture for a small firm, where he's given a crash course in the uniform dogma of American business. The firm's owner, Mr. Jones (the excellent Jack Thompson) even foists Dale Carnegie's book (the bible of the mongering and huckster class) on Sam to memorize.

Between absorbing Carnegie's sermons on success, Sam's life continues to unravel. His estranged wife (Naomi Watts) wants nothing further to do with him, while his attempt at gaining a small-business loan to start his own enterprise (a misguided idea to sell tires door-to-door, like toiletries) meets rejection. Sam begins to truly see himself as a slave to a corrupt system. He fixates on finally making a name for himself by dramatically attacking the very seat of American power.

As with the real Bicke, Sam begins to plot his assassination-by-airplane scheme, writing down the rationale for his actions, which he posts to composer Leonard Bernstein (this one-sided correspondence is explored in Stephen Sondheim's musical Assassins). But, being the antithesis to Midas, since everything he touches turns to crap, Sam even flops here.

Penn is impeccable, especially in realizing the excruciating sincerity and impotent rage of Sam, or when he captures those bleak moments of the soul when Bicke is bathed in the sweat of futility. Penn makes the scenes of Bicke's eight-hour incarcerations in the office furniture showroom powerfully cathartic for those of us who've silently suffered through menial jobs.

Assassination bears some semblance to Scorsese's superior Taxi Driver (beyond the happy similarity between "Bicke" and "Bickle"), though Scorsese managed to place De Niro's Travis Bickle within the larger context of dystopic America. And this is where director Niels Mueller fails, for as "small" as Sam feels, and as truly unnoticeable as the average man in America is, we never see Bicke in contextual long shots. Instead, through close and medium shots, we are given little other than Penn himself, and he overwhelms the material.