Nothing so polarizes Americans as the issue of abortion. Long before pundits began tossing around the notion of red states and blue states, the country was segmented by a kind of psychic fault line, over which debates about a woman’s right to terminate her pregnancy in a safe and legal manner have fractured into sometimes violent conflict: abortion clinic bombings, assassinations of physicians, and a fundamentalist rage that seems intent on burning the Constitution if that would fulfill its ends.

Yet anyone expecting “Lake of Fire,” Tony Kaye’s profound and direct exploration of the issue, to be another hot potato “doc-buster,” preaching to a (presumably liberal-centrist) choir with a smug “gotcha!” sensibility, will be rattled by this courageous, excessive, and powerfully unresolved piece of work. Over the course of 158 minutes, strident advocates on both sides of the abortion question hammer away, their faces framed tightly in the grainy shimmer of 35 mm black-and-white (and high-definition video) that serves a key aesthetic effect: Drained of color, the screen offers nothing to distract from its rhetorical tilt. There are no ironic musical cues, no celebrity cachet, no gimmicks, and no easy answers.

Mr. Kaye, a British filmmaker known for 1998’s “American History X,” a drama about the neo-Nazi movement, clearly has an affinity not only for American culture, but for the tensions and absurdities that underpin its façade of apple-pie normalcy. He began shooting “Lake of Fire” in 1990, and simply kept going, apparently unable to stop. He was somehow able to visit many of the major flash points, attending rallies, trailing right-to-life protesters outside Southern abortion clinics, and viewing funerals of doctors murdered by would-be Christian martyrs for the cause. He even traces the arc of one zealot, Paul Hill, from picket line to courtroom to lethal injection for the 1994 shootings of Dr. John Britton and his escort, James Barrett, outside a Pensacola, Fla., clinic.

At the same time, the director also took his camera inside clinics to observe the procedure, showing aborted fetuses as their fragmented bodies are examined, piece-by-piece, in steel sinks. Initially, the women who are interviewed before or after their abortions are shown only from the back. But eventually, after two hours of sound and fury, Mr. Kaye fixes on a woman named Stacey, whose troubled life on America’s class margin becomes emblematic of the issue in ways both touching and depressing. Stacey becomes a contemporary version of Norma McCorvey, the once-anonymous plaintiff in the landmark 1973 Supreme Court decision Roe v. Wade, which legalized abortion in America. Today, Ms. McCorvey is a born-again Christian campaigning on behalf of the pro-life cause.

Since he financed the effort out of pocket, Mr. Kaye could indulge his obsession endlessly. It’s a rare circumstance for any filmmaker. Because of its 17-year gestation, “Lake of Fire” becomes a shadow history of post-1990 America, one that uses the abortion issue as an axis around which a full spectrum of characters whirls. One wishes that, for all his effort at chasing balance, Mr. Kaye might have found fewer obvious crackpots arguing against abortion. In stretches, “Lake of Fire” — which takes its name from the eternal torment promised sinners in the Bible — feels like an Errol Morris documentary fueled by drugs, firearms, and hallucinations of Jesus.

“Intolerance is a beautiful thing,” declares Randall Terry, the gay-bashing leader of Operation Rescue and, more recently, a proselytizing radio host. He’s one of the milder figures Mr. Kaye follows. More clarity is offered by third-party pundits like the jazz critic and civil liberties commentator Nat Hentoff. His anti-abortion stance, he says, is consistent with a pro-life perspective that also opposes the death penalty and supports anti-poverty initiatives. Such rationality, from an atheist no less, is an anomaly here.

Even as the talking heads begin to jar your senses, though, “Lake of Fire” is an incredibly valuable act of filmmaking. Mr. Kaye insists on doing things that network news divisions are too frightened to even attempt, now that they’ve all been sold out to corporate profit margins and the shallow glimmer of “infotainment.” This camera flinches at nothing. His contemporaries better take note.

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