The higher they are, the harder they fall.

The face of NBC News blew it. NBC Nightly News managing editor and anchor Brian Williams plopped down from his pedestal where his fans, bosses and viewers have placed him because he, um, misremembered being shot down by a rocket-propelled grenade in Iraq.

And if NBC News has any shred of decency, Williams's career at NBC News is toast. He broke the cardinal rule of journalism: he lied.

If I'm reading the accounts right, Williams actually believed he had been shot down. He deluded himself into thinking that he was a hero.

How in the world is that possible?

Here's the quote that does him in:

WILLIAMS: We were in some helicopters. What we didn't know was we were north of the invasion. We were the northernmost Americans in Iraq. We were going to drop some bridge portions across the Euphrates so the 3rd Infantry could cross on them. Two of our four helicopters were hit by ground fire, including the one I was in.

And here are the accounts of veterans knocking him down. "Sorry dude, I don't remember you being on my aircraft," wrote Lance Reynolds. "I do remember you walking up about an hour after we had landed to ask me what had happened. Then I remember you guys taking back off in a different flight of Chinooks from another unit and heading to Kuwait to report your 'war story' to the Nightly News. The whole time we were still stuck in Iraq trying to repair the aircraft and pulling our own [s]ecurity."

"Such a liar!" wrote Chris Simeone. "I was the Pilot in Command of the CH-47 flying Brian Williams into Iraq during the invasion. He was on my aircraft and we were NOT shot down. That was a sister ship and a friend of mine. Brian Williams has been knowingly lying since that mission to boost his credentials. As far as the soldier, he deserved to be recognized! They were a help to us. As far as Brian Williams, he's a fake."

As a card-carrying member of the media, I hate having to write about errors in the news biz. We already have a bad enough reputation. And I hate to see someone who has worked so hard for his entire career, who is good at his job, get whacked for a mistake. But a lie is a lie. It is not just a "mistake," as he said in his brief apology on his program.

Look, I know that in the grand scheme of life, this isn't really a big deal. Terrorists are slitting journalists' throats and sending out videos proving it. Williams misremembered something. Is he evil? Probably not.

But what does this say about his credibility? Is he living in a fantasyland, breathing his own great press? Absolutely. This is a man who is paid millions of dollars to get his facts straight. He didn't. And he should be penalized for it.

Ashburn is an award-winning Washington-based reporter and TV analyst covering media and politics.