As sweet as vinegar and full of contempt for politically correct sentimentality, Jody Hill’s near-brilliant black comedy, “Observe and Report,” manages to do for minimum-wage security what “A History of Violence” did for the American institution of small-town seclusion: It exposes its shadowy underbelly and destroys its characters own self-delusions about their place in the world.

A loving parallel to Martin Scorsese’s uncompromising “Taxi Driver,” Hill’s bleak glimpse at the world of mall cops is a scathing rebuke of mindless machismo, and yet the film never wastes a single moment, constantly barraging the audience with the nastiest humor one could imagine and crushing the audience’s defenses. If that sounds like the film is trying too hard to shock, that’s fairly true. However, the drive of the narrative and its single-minded attempt to get at the heart of its demented main character make it far more entertaining and insightful than it has any right to be.

Like Robert De Niro’s Travis Bickle, Ronnie Barnhardt (Seth Rogen) is the world’s greatest force for good, a pillar of justice in a sea of mediocrity and immorality. At least, that’s what he thinks. In reality, Ronnie is the head security guard at a banal shopping mall, whose main duties consist of keeping skateboarders out of the parking lot and keeping a watchful eye on Brandi (Anna Faris), a ditz who never leaves her post at the cosmetics counter and has no interest in keeping a civil tongue in her mouth and is even less interested in returning Ronnie’s obsessive affections.

The complacency of this haven for commerce abruptly turns on its head when a flasher finds his way into the parking lot, scaring off dozens of women, including Brandi, who is so scarred by the event she can’t even move. Ronnie, whose delusions of grandeur are dangerous enough without real antagonism, sees this as a chance to prove his worth as a savior, taking on a creepily paternalistic role in Brandi’s life and constantly haranguing the real police, represented by Detective Harrison (Ray Liotta).

Throughout the film, Ronnie’s bizarrely sincere fight for truth, justice and the American way grows more and more into a liability, as he hinders investigations and drifts away from his real duties to pursue his own career in the police force, going so far as to force Harrison to give him a tutorial in the day in the life of a cop. This scene, where Harrison ditches Ronnie in a truly nasty part of town, is the film’s turning point, the scene that either makes or breaks the film for the audience. Facing off against a sadistic drug dealer (Danny McBride, in a potent cameo), Ronnie actually kills six men single-handedly and brings one of their children into custody. The audience is invited to laugh at death and vigilantism in an astonishingly frank light.

Rogen is a peculiarly charming actor, not always funny, but never unlikable. He gives an immersive, star-making characterization, challenging preconceptions about his own star persona and simultaneously reinventing himself as a nuanced performer. Faris, unlike most women in comedies, is actually allowed to be funny, while Liotta and Michael Peña, who plays Ronnie’s right-hand man, get shining moments.

While it sometimes lags in pacing, “Observe and Report” uses “Taxi Driver” as more than just a jumping-off point. Hill’s vision depicts inhumanity bluntly and in a somewhat glamorous fashion, and though it is always clear that it is just a film, “Observe and Report” strikes a nerve of moral ambiguity like no other studio comedy found in today’s multiplexes.

“Observe and Report” was written and directed by Jody Hill.