Possibly the most comforting of current small-screen offerings, and so among the most successful, is Dick Wolf’s ultrareliable Law & Order, a catch-‘em-and-(mostly)-convict-’em series as no-nonsense as its title, rerun four times a day by A&E and used by NBC like a Dutch boy's thumb wherever the schedule springs a leak. Now a second series has been constructed upon that rock-solid foundation, Law & Order: Special Victims Unit, which deals exclusively with sex crimes and recapitulates most of the virtues of its predecessor, along with its music, blackout format, ripped-from-the-headlines plotlines and almost Dickensian interest in class, from pavement to penthouse. (Both shows take especial delight in bringing down the high and the mighty.) What primarily distinguishes the franchise, however, is the ruthless efficiency with which it does business -- it’s Dragnet, essentially, without the weirdness -- and, apart from Jerry Orbach‘s smutty asides in the old show and Richard Belzer’s paranoid one-liners in the new, the avenging angels of both teams are as serious and single-minded as can be. It‘s a no-fat, no-frills approach. Cops and criminals alike, while everyone has his tics and backstory, count less here as individuals than as abstractions -- as embodiments of ideas and attitudes, the clash of which will lead to heated argument, facts and figures, and righteous pronouncements on the demerits of the system and the terrible way of the world. (That Law & Order is so abstract may explain the ease with which it’s weathered numerous cast changes; the players are fundamentally interchangeable.)

Though Special Victims Unit seems to take more of an interest in the private lives of its principals -- principally top-lined detective Chris Meloni (Oz), whom we regularly follow home to his wife and four kids -- it‘s really only to reflect from another angle what’s going on at work: We see Meloni give his oldest daughter hell for sneaking out at night, attempt to discuss virginity with his middle daughter by way of soccer metaphors, and fret over the safety of his little boy in a world where child molesters are not incinerated upon conviction. Partner Mariska Hargitay (Jayne Mansfield‘s daughter, I never tire of marveling) has also been given some relevant extracurricular history -- she was conceived by rape -- but with or without that character point she’s a classic L&O woman, good-looking and sharp-edged and nobody you‘d want to mess with, and when equally classic Law & Order assistant D.A. Angie Harmon comes around, as she has a couple of times, you can hardly tell them apart. Dann Florek, who gave the orders around L&O in its first seasons, has been drafted back into service, though the more remarkable cross-series casting is the importation of Belzer’s Detective John Munch from Homicide: Life on the Street, with which Law & Order was wont to cross stories during sweeps; it‘s an easy fit and an interesting idea -- old characters never die, they just find a new job. Junior investigators Dean Winters (also from Oz, where he is scary) and Michelle Hurd, who seems to be getting the least screen time, round out the cast.

It’s well-made and well-played, as engrossing as the original model; once the wheels begin to grind, it‘s hard to look away. And yet I am not convinced that America really needs a television series devoted to sex crimes. (And this one runs twice a week; in the new spirit of what’s called “repurposing,” the USA Network, whose Studios USA co-produces the show, runs each episode Sunday nights at 11 p.m., 13 days after its NBC premiere.) In spite of the best intentions and most thoughtful execution, and notwithstanding whatever “educational value” the material may have, there is something unavoidably, oddly exploitive about the concept. Murder is one thing -- it‘s so central a part of our storytelling history that it has become, in an emotional sense, transparent; it can as easily be the pretext for comedy as for tragedy. Sexual violence is another matter -- not a worse one, obviously, but more complicated and certainly more private -- and it makes for strange entertainment, even if justice is done.