This column begins with your periodic reminder that In Real Life, I teach high school English. I often teach Tim O'Brien's novel "The Things They Carried," as a whole or in pieces, including the chapter "How to Tell a True War Story" (warning: that story is not for the squeamish; there's some language and violence and other Vietnam War kinds of stuff not everyone will appreciate).

I've been thinking a lot about that story lately, as NBC anchor Brian Williams, Bill O'Reilly, and even Wisconsin Governor Scott Walker have all been in the news lately for telling untrue war (or "war") stories.

What I like about O'Brien's story is that the author, a veteran and kind of famous for writing war stories, lays out some rules that people, like my students, who haven't been through war can use to test the veracity of the war stories we hear. We put other war stories, from Ambrose Bierce to Elie Wiesel, to the test: which are true? And what about Williams and O'Reilly and Walker?

Mostly, O'Brien says simply that the verifiable facts of a particular story have nothing to do with whether a story is "true" or not. "In many cases," he writes, "a true war story cannot be believed. If you believe it, be skeptical." Believable things, he tells us, is just there to make the true craziness of war seem plausible. If the truth were told unadorned with "normal stuff," in his words, the pure craziness of actual war would never be believed.

This is why I kind of feel bad for Brian Williams. As he told "Stars and Stripes," the flubbed version of his story – that he was on a helicopter that took RPG fire, when the one hit was ahead of his – was told in an attempt to recognize "a 23-year returning Army veteran with three Bronze stars," and not in any way to aggrandize himself. Indeed, he'd told the story more accurately many times before that, on the news and on his blog.

The crazy part of Williams' story is not factually in question. For a nation with such a sensitive military trigger, few of us will ever see war; after World War II, according to a recent essay in The Atlantic by James Fallows, 10 percent of Americans were or had been on active duty. Less than one percent of us, Fallows notes, served in Iraq or Afghanistan after the September 11 attacks.

So when Williams says, here is a man who served for two decades, surviving across multiple war zones and acting valiantly in the face of incredible peril, that's kind of crazy. It's completely normal for Williams, a journalist who saw a number of dangerous situations in combat covering our recent wars, to offer that he had witnessed one such dangerous incident himself. That's what he adds to make this veteran's story credible, relatable, normal for the 99 percent of us who never served but have watched the news before.

Reading and hearing Williams' apologies after the fact, it seems clear that he feels absolutely terrible that all of this focus on him has distracted from his real purpose, to honor someone else.

Bill O'Reilly, on the other hand, is not interested in other people's honor. Instead, it's all about his own stature. When he claims to have been in a war zone in Argentina or to have seen or heard grisly murders and suicides, besides not being true, none of that is to honor anyone else, but to make himself seem like something more than he is. Many of the incidents in question seemed to come when O'Reilly felt he needed to defend himself: Look, I've been in a war zone, okay?!? he shouts when questioned.

O'Brien warns us about that. True war stories, he said, don't have such obvious meaning. "In a true war story, if there's a moral at all, it's like the thread that makes the cloth," he writes. "You can't tease it out." It's especially telling that no character in O'Brien's novel ever tries to lay out a story's moral himself or, for that matter, use a war story as a defense of anything, especially not himself.

While O'Brien also tells us that "it's safe to say that in a true war story nothing much is ever very true," that doesn't excuse what O'Reilly has done here. O'Brien says that, because in war, "you lose your sense of the definite." The specific details may be wrong, he says, but the truth of the situation, of the sentiment behind it, is never in question.

O'Reilly has, since reporters at "Mother Jones" magazine first questioned his Falklands war stories and other outlets have raised doubts about his work in El Salvador, in Northern Ireland, and even covering the Rodney King riots in Los Angeles, changed his stories and offered more honest details. It seems O'Reilly's sense of the definite is just fine -- a clear signal that, by O'Brien's definition, his war stories are not true.

Which brings us to Scott Walker. Walker has never been anywhere near an actual war zone on any continent and, my critics will undoubtedly argue, has not claimed to be. So why bring it up? Is it just my Walker Derangement Syndrome?

I'll start with one of my all-time favorite Walker fact-checks, that "protesters surrounded his car, blocked his exit and rocked the vehicle after a 2011 appearance in La Crosse." That received a straight-up "false" rating.

But Walker put that story in his book to show readers from outside the state, readers who might one day be presidential primary voters, just how dangerous life for the governor had been since he decided to take the fight to unions.

"We were dealing with people who were so blinded by their anger," he wrote, "that they were not in the least bit afraid to storm and shake a police car. We had never seen anything like it in Wisconsin before." I mean, "we" didn't even see it then, let alone before, but that's beside the point.

The point is perhaps better illustrated by the now-infamous statement Walker offered at the Conservative Political Action Conference last week (and several times before), that because he was able to "take on 100,000 protesters" as governor, he would be able to handle a well-armed apocalyptic death cult like ISIS as president of these United States.

These are Walker's war stories. Like the ones Bill O'Reilly told, Walker's are told solely to build himself up. And they are not true, not true factually -- Walker never once confronted us while we marched, instead moving in and out of the capitol through underground tunnels -- or true in the Tim O'Brien "How to Tell a True War Story" sense.

"In the end," O'Brien writes, "a true war story is never about war." Yet that's all Walker talks about, especially in the face of questions about, say, real policy. He wants people to know about his personal war, and about the way he personally has acted valiantly in the face of incredible peril.

And that is probably the biggest untruth of all.