Just when you thought you could put to bed the idea that the Kennedy assassination was a conspiracy, along comes a thriller that makes you think that such an intricately-planned operation could not have been the work of one loser. "Arlington Road," a political blockbuster that recalls Alan J. Pakula's "The Parallax View," deals more with large-scale terrorist activity in the U.S. than with a plot to assassinate one man. But by carefully showing the enormous amount of planning that political criminals make to carry out a plan by clockwork, Mark Pellington's tingler--from a script by Ehren Kruger that alternates flashes of intense anxiety with moments of almost sluggish meditation--cannot help giving the viewer the impression that guys like Lee Harvey Oswald are mere patsies for sophisticated and malevolent schemers.

Summoning memories of the bombings of corporate and governmental buildings in New York and Oklahoma City, "Arlington Road" recollects events as diverse as the recent bloodbath at Columbine High School and, in fact, rumor has it that the opening of the film was postponed in deference to that cataclysmic incident. But while "Arlington Road" has obligatory moments of savagery, director Pellington is far more interested in portraying the steady emotional deterioration of a good man who is already on edge because of the recent tragic death of his wife--an F.B.I. agent who had been gunned down in a botched raid on a presumed right- wing cult. Like "The Parallax View," this film shows how a cerebral fellow becomes increasingly frightened to the point of paranoia each time he uncovers new evidence of a far- reaching political conspiracy. Whereas in Alfred Hitchcock's "Psycho" and currently in Spike Lee's "Summer of Sam" the paranoid personalities are exhibited as is, in Ehren Kruger's script we observe how a man's mental state steadily and rapidly declines as his research into an alleged criminal unfolds new confirmations. However unbalanced the central character's faculty becomes, the viewer cannot help coming away from this movie with the sense that this disintegration can happen to any of us, given the right circumstances.

The opening scene, photographed by Bobby Bukowski as though events were taking place in a drug-induced nightmare, reveals a frightened 9-year-old boy running spastically across a suburban road, blood dripping slowly onto his sneakers. His life is saved by American History teacher Michael Faraday (Jeff Bridges), who happens upon the lad while he is driving home and rushes him to a hospital. This incident leads to Faraday's being introduced to the boy's parents, Oliver Lang (Tim Robbins) and Oliver's wife Cheryl (Joan Cusack)--who until then have pretty much kept to themselves. Both Faraday and Lang have been emotionally on edge, the latter for an event which occurred when he was a teenager, and Faraday for having lost his F.B.I.-employed wife who was gunned down in a shootout. Faraday has meanwhile hooked up with a former graduate assistant, Brooke Wolfe (Hope Davis) to whom he confides results of research into his neighbor's background. Insisting that Lang is involved in a murderous conspiracy against the federal government, he fails to convince either Brooke or his contact in the F.B.I., Agent Whit Carver (Robert Gossett). Unable to sway the people closest to him, Faraday increasingly loses his balance.

At many points in this frequently pulsating film, Bridges has a difficult time convincing the audience as well. One of America's finest actors, Bridges--perhaps the current decade's answer to Robert Mitchum--is best known for his hangdog and manic expressions, as in his performance as a wastrel in "Cutter's Way" and as well for the energy he exhibits in "Tucker." He was at his best in Peter Weir's 1993 film "Fearless" as the stunned survivor of a plane crash who is unable to cope with his family but finds solace with another survivor who has lost her baby in the same accident. This time around, his character must deal not only with the pain of losing his wife so tragically in a gun battle but with the knowledge that he is on to a major conspiracy while the people he leans on the most are patronizing, if not simply skeptical.

Sandwiched between a high-strung opening and a tension- filled conclusion, "Arlington Road" is, like Alan J. Pakula's "Consenting Adults," yet another take not simply on what distress kindles beneath the competent surface of educated people but as well with the danger lurking under the civilized and manicured veneer of a picturesque suburban community. During World War 2 a popular expression about Australia was "there's no hiding place down there." Pellington reinforces that concept with his new movie. While two vast oceans serve as America's moat protecting the republic from foreign invasion since 1814, and while the Cold War is now a fading memory, we must confront the enemy that lurks within. Whether you live in New York's Columbus Circle or the suburbs of Columbus, Ohio, you can never feel confident of your safety. Michael Faraday makes that point clear in his passionate lectures to his classes at Georgetown University. Oliver Lang hammers the subject home, his quiet suburban life with his all-American family belying a nefarious intrigue.

Yes, Virginia: people can indeed be pushed over the edge by events beyond their control. Jeff Bridges' performance as an already tormented man driven to psychosis by the loss of his wife, the kidnapping of his boy, and research that convinces him of a fiendish design against his government, is both frightening and persuasive. "Arlington Road" is rousing summer entertainment.