By Cheryl Eddy

IN 1974 WOULD -be presidential assassin Sam Byck plotted to hijack an airplane and crash it into the White House. Byck and his elaborate scheme – previously dramatized in musical form, via Stephen Sondheim's Assassins – seemed harebrained at the time but naturally took a more sobering cast post-9/11. Inspired by this true story, Niels Mueller's resolutely downbeat The Assassination of Richard Nixon studies what might drive a person (specifically, a garden-variety sad sack who doesn't happen to be a religious fundamentalist, Manson follower, or fall-guy pawn in a political conspiracy) to such extremes.

Hatred of Nixon isn't even the focus of Mueller's fictionalized Sam, here renamed Sam Bicke and embodied, with simmering frustration masked by a wimpy exterior, by Sean Penn. Estranged from his wife, harried waitress Marie (Naomi Watts), and three kids who are indifferent to his existence, Bicke toils as an office furniture salesman, peddling wastepaper baskets in shades of avocado and "harvest gold." His boss (Jack Thompson) supplies Bicke with The Power of Positive Thinking and a series of motivational tapes ("The salesman who believes is the salesman who receives!") but belittles him at every opportunity, even requiring him to shave his mustache ("Now you look like a family man, instead of some schmuck with a pussy on his face"). Bicke's only pal, Bonny (the ubiquitous Don Cheadle), tolerates his moodiness, but only to a point; Bicke's brother and former employer (Michael Wincott) condescendingly views him as a lost cause.

Nervous and awkward in person – and socially clueless enough to seek out a Black Panther and propose the group change its name to "Zebras," so sympathetic white folks can join the cause – Bicke is confident only in voice-over, relaying his feelings in a series of tapes he eventually (and somewhat inexplicably) mails to Leonard Bernstein. Though the real-life Byck made similar recordings, the monologues here are clearly penned (by Mueller and coscripter Kevin Kennedy) to underline the film's themes, especially "All I want is a little piece of the American dream." Bicke's other rants revolve around waiting (his twin agonies: the unresponsive Marie and the outcome of a slow-moving loan application), the plight of the little guy, liars, and the unfairness of "the system."

In Assassination's press notes, Mueller insists that since his protagonist's real name actually was Byck, with only the spelling altered in his film, any and all similarities with a certain Travis Bickle are entirely coincidental. But "Bicke" versus "Bickle" aside, the comparisons are undeniable; though Robert De Niro's Taxi Driver character descends into violence more urgently than Bicke, who grapples with fetal-position depression (but alas, no Mohawk, just the return of his moustache), both men are disaffected, blue-collar loners sneering at the scumbags of the world – politicians in particular. Nixon pops up on every TV that crosses Bicke's eyeline, waltzing with his just-married daughter, lecturing about the importance of "competitive spirit," and declaring, inevitably, "I am not a crook."

But Assassination isn't a stylish, statement-making, era-defining picture on par with Taxi Driver. Penn's beautifully detailed performance aside – his Bicke is a guy so unsure of himself, he'll kick over a garbage can in anger, then quickly make things tidy again – Assassination sometimes feels as beige as its mid-1970s color scheme. Despair prevails in scene after scene, but Bicke is such a pathetic guy that it's hard to get in his corner. We can see why his boss ridicules him, because he's a terrible salesman; we can see why Marie is irritated by his pitiful presence. Dread, rather than suspense, is the only thing that builds throughout; Assassination isn't a political thriller on the garish, jolting scale of the recent Manchurian Candidate remake, and its flashback-heavy structure brings the rock-bottom Bicke (shortly pre-hijack attempt) to the forefront in Assassination's first minute.

After a movie's worth of worst-case scenarios, it's actually a relief to get to the fast-paced climax, a startlingly violent airport scene that re-creates Byck's – and Bicke's – final failure. Here, it's tempting to imagine why Penn, who's been outspoken enough against the current administration to get puppet-ized in Team America: World Police, would be drawn to this role. When Bicke wonders, "This is a good country, filled with good people, but what good is good in times like these?," it's easy for any rational-thinking, Bush-hating person to agree.

But when Bicke rehearses walking through the terminal's metal detector with a weapon strapped to his leg, fantasizing about making "a real change," the shadow of 9/11 looms large. In the wake of real planes crashing into real buildings, and subsequent "real changes" in the government (farewell, personal freedom!), the end result hardly resembles any American dream – especially Bicke's sadly simplistic vision of self-made career success, family unity, the acquisition of a shiny new Cadillac, and a world where everyone always tells the truth.

'The Assassination of Richard Nixon' opens Fri/7, Embarcadero Center Cinema, 1 Embarcadero Center, Promenade Level, S.F. (415) 267-4893; Shattuck Cinemas, 2230 Shattuck, Berk. (510) 464-5980. See Movie Clock, in Film listings, for show times.