NEW YORK — “NBC News magazine …”

There’s a phrase we haven’t heard nor seen in quite a few years. Yet once upon a time — and this seems so long ago and far away now — it popped up reliably on every new fall schedule, like a gate-crasher at some chic launch party. There were 17 attempts over a two-decade period starting in the late ’60s. All shared one fate — failure — until “Dateline NBC” erased the curse in 1992.

In the run-up to the launch of “Rock Center with Brian Williams” Monday night, NBC executives have said a bona fide NBC News magazine hasn’t launched since then, although that is a bit of historic revisionism designed to erase another failed attempt — “Now With Katie Couric and Tom Brokaw,” which folded after a brief run in 1994.

All this simply points up the obvious: Newsmagazines, particularly with those three initials N, B and C appended, are a tough sell. Viewers typically want true crime in their so-called prime time “news” diet, if they want it at all, while tolerating substantive journalism only from “60 Minutes.” As a result, the networks — and especially NBC — have long since moved on to more pressing concerns, like finding a killer sitcom or drama. For this reason, “Rock Center” is an intriguing development.

Why a newsmag and why now? “The flip answer, I suppose, is that no network news division has been brave or bold or ambitious enough to try it until now,” says Rome Hartman, “Rock Center’s” executive producer, “although obviously, network prime time programming is a bit of a dark art, and it’s cyclical, for sure. Trends come and go, and while the magazines that are on the air have turned out to be quite hardy and long-lived … except for ‘60,’ they morphed into something different from what they were originally conceived to be.”

This means that there’s an opportunity. “Rock Center” is expected to be a traditional TV newsmagazine much like “Primetime” or “20/20” (which is now often single-topic) once were — with one difference. The pieces will be taped, but the intros by “NBC Nightly News” anchor Brian Williams will be live. In fact, “Primetime” was also initially live until “live” proved awkward (such as the time anchors Diane Sawyer and Sam Donaldson went to a live shot … of a tree).

But more importantly, “Rock Center” is expected to be weighty — no crime-of-the-week story need apply, or so Hartman and others insist.

Williams said, “I can’t say this often enough, but no one has mentioned any kind of bracket for success or the standards for that. All we’ve been told is to go do the broadcast we’d like to watch, the broadcast we’ve always wanted to work on.”