It seems entirely possible that the current impact of Harvey Keitel’s unnamed but aptly titled cop in Bad Lieutenant could be blunted by almost two decades’ worth of poorly behaved cops in movies and on television. Surely regular viewers of The Shield wouldn’t gasp much as Keitel stumbles through drinking, drugs, gambling, and thievery—though maybe they’d be taken aback at the famous scene where he harasses a pair of teenage girls

What keeps Bad Lieutenant interesting years after an NC-17 rating and accusations of blasphemy, though, is director Abel Ferrara’s approach to this character. The movie follows the lieutenant on his daily business, essentially a long drug buffet with some perfunctory police work on the side.

Ferrera shoots in long, often stationary takes, unblinking in the face of Keitel’s self-destructive misery, lingering on his face or, in the more distant shots, the environments in which he awakes from his stupor: a trashed church pew, a drug den, a nice house in the outer boroughs where he stashes his vaguely mournful-looking family. For a movie about extreme behavior, Bad Lieutenant is unusually observant.

After about half an hour, the movie introduces its sort-of story: a young nun is raped by a pair of miscreants, and while the lieutenant doesn’t do much at first – most of his investigations involve stumbling around the peripherals of cases, shaking down other cops for sports bets – the crime gets under his skin. The nun (Frankie Thorn) has such steadfast faith that she forgives her attackers, and shows no interest in cooperating with the cops to catch them. When he’s sober enough to comprehend this, the lieutenant, a mega-lapsed Catholic with a rosary hanging from his rearview mirror, brings his ongoing crisis of bad faith to a boil.

Dealing with the Catholic material, the movie is occasionally histrionic, lapsing into sort of a poor man’s Scorsese when it cuts to a shot of Jesus on the cross screaming in agony during the nun’s rape, or during any number of scenes requiring Keitel to howl with similar agony. Mostly, though, Bad Lieutenant plays out as a dispassionate, keen-eyed character study that happens to contain a ton of swearing, sex, and horrible violence. It’s not outmoded by advances in bad-cop cultural figures because it’s not chasing that kind of secret glamorization.

The extras on the new special-edition DVD are simple but effective: a behind-the-scenes feature, and a commentary track featuring Ferrara and his cinematographer Ken Kelsch. Ferrara’s chatty, rumbly commentary has plenty of personality, with anecdotes about real cops as well as the shoot, but the retrospective making-of material is both more comprehensive and more concise.

Presented in three parts, the feature tracks the movie from the idea stage to its critical reception. The earliest material is especially interesting, revealing that the film was based on “goofy ideas”, in Ferrera’s words, and vignettes that eventually fit together into a scant 68- page script for a production that encouraged improvisation. This loose structure somehow gave way to a tightly focused movie; if you were to mount a case for the importance of directing over writing in movies, Bad Lieutenant could probably be used as an exhibit.

The feature also reveals that Christopher Walken was originally set to play the lieutenant, but backed out at the last minute, paving the way for one of Harvey Keitel’s most acclaimed performances. “Chris is too elegant,” says one crew member. “Harvey’s not elegant.” The gloriously inelegant Keitel is noticeably absent from the DVD extras, though, unable to comment on his own work. Maybe it seemed beside the point; the unnamed, anguished cop bulldozes over everything else in his path anyway.