WASHINGTON . THIS was a bomb that had been ticking for a while.

NBC executives were warned a year ago that Brian Williams was constantly inflating his biography. They were flummoxed over why the leading network anchor felt that he needed Hemingwayesque, bullets-whizzing-by flourishes to puff himself up, sometimes to the point where it was a joke in the news division.

But the caustic media big shots who once roamed the land were gone, and “there was no one around to pull his chain when he got too over-the-top,” as one NBC News reporter put it.

It seemed pathological because Williams already had the premier job, so why engage in resume inflation? And you don’t get those jobs because of your derring-do.

When Williams was declared the hair apparent to Tom Brokaw in 1995, hailed by Jay Leno as “NBC’s stud muffin,” I did a column wondering why TV news programs only hired pretty white male clones. I asked Williams if he was an anchor android.

“Not that I’m aware of,” he said gamely, in his anchor-desk baritone. “I can deny the existence of a factory in the American Midwest that puts out people like me.”

Williams told friends last week that he felt anguished, coming under fire for his false story of coming under fire.

Although the NBC anchor had repeated the Iraq war tall tale, ever more baroquely, for more than a decade, when he cited it on his Jan. 30 broadcast during a segment about going to a Rangers game with a retired, decorated soldier who had been on the ground that day when he landed, Williams got smacked down on Facebook.

A crew member from a Chinook flying ahead of Williams, who was involved in the 2003 firefight, posted, “Sorry dude, I don’t remember you being on my aircraft. I do remember you walking up about an hour after we had landed to ask me what had happened.” Stars and Stripes ran with it, and, by Saturday, Williams announced that he was stepping down for several days.

Social media . the genre that helped make the TV evening news irrelevant by showing us that we don’t need someone to tell us every night what happened that day . was gutting the institution further.

Although Williams’s determination to wrap himself in others’ valor is indefensible, it seems almost redundant to gnaw on his bones, given the fact that the Internet has already taken down a much larger target: the long-ingrained automatic impulse to turn on the TV when news happens.

Although there was much chatter about the “revered” anchor and the “moral authority” of the networks, does anyone really feel that way anymore? Frothy morning shows long ago became the more important anchoring real estate, garnering more revenue and subsidizing the news division. One anchor exerted moral authority once and that was Walter Cronkite, because he risked his career to go on TV and tell the truth about the fact that we were losing the Vietnam War.

But TV news now is rife with cat, dog and baby videos, weather stories and narcissism. And even that fare caused trouble for Williams when he reported on a video of a pig saving a baby goat, admitting “we have no way of knowing if it’s real,” and then later had to explain that it wasn’t. The nightly news anchors are not figures of authority. They’re part of the entertainment, branding and cross-promotion business.

Former ABC News anchor Diane Sawyer trended on Facebook for reportedly scoring the first interview about Bruce Jenner’s gender odyssey.

When current ABC News anchor David Muir was still a correspondent, some NBC News reporters had a drinking game about how many times he put himself in the shot and how many times his shirt was unbuttoned.

As the late-night comic anchors got more pointed and edgy with the news, the real anchors mimicked YouTube.

Williams did a piece on his daughter Allison’s casting in an NBC production of “Peter Pan.” And Muir aired an Access Hollywood-style segment with Bradley Cooper.

As the performers . Jon Stewart, Stephen Colbert, John Oliver and Bill Maher . were doing more serious stuff, the supposedly serious guys were doing more performing. The anchors pack their Hermes ties and tight T-shirts and fly off to hot spots for the performance aspect, because the exotic and dangerous backdrops confer the romance of Hemingway covering the Spanish Civil War.

Oliver, who has made waves with pieces on financial chicanery in the Miss America contest and the corporate players trying to undermine net neutrality, told The Verge that he is hiring more researchers with backgrounds in investigative journalism.

Meanwhile, in an interview with Fusion, Muir acted out the facial expressions he uses during his broadcast: “the listening face,” the “really listening” face, and the “really concerned” face. All that was missing was “Blue Steel.”

With no pushback from the brass at NBC, Williams has spent years fervently “courting celebrity,” as The Hollywood Reporter put it, guest starring on “30 Rock,” slow-jamming the news with Jimmy Fallon and regaling David Letterman with his faux heroics: “Two of our four helicopters were hit by ground fire, including the one I was in, RPG and AK-47.”

As his profession shrinks and softens, Williams felt compelled to try to steal the kind of glory that can only be earned the hard way.