It can sometimes seem that not since the Civil War has America been as challenged or divided as it is currently. To that contention, Ken Burns and Lynn Novick’s documentary “The Vietnam War” is a 10-part counter-argument.

amExpress spoke recently with Geoffrey C. Ward, Burns’s longtime collaborator and writer of the documentary and accompanying book. Ward recalled the strange experience of investigating a history he and many of his viewers lived through.

In “The Vietnam War,” he and the directors weave the stories of soldiers, civilians, protesters, diplomats, politicians, spies and war correspondents into an 18-hour epic. It’s often a picture of confusion (particularly among the leaders), and mistakes about to be made.

Ward says history doesn’t exactly repeat itself, but it’s hard not to wonder whether we can avoid the tragic outcomes repeatedly depicted over the course of the series, the final episode of which airs Thursday.

What’s the role of a writer for a documentary series?

I write the script. When [narrator] Peter Coyote is talking, that’s me.

How much does the script change over time, as you start slotting in the interviews?

The story changes and alters and you realize you can have witnesses tell the story another way. A lot of writing film is removing things. You find that the images can replace narration.

You try to find a marriage between them. For example, pictures can’t tell you a complicated story about diplomacy. You can see an anguished president or an exuberant meeting, but you need writing to explain why they’re exuberant or what happened at the event. But sometimes a picture simply of an anguished President [Lyndon] Johnson can literally speak volumes.

You’ve written other histories, but is this the only project where you’ve lived through the histories?

That’s right. And that was very educational. This really was events that happened during my lifetime, that focused the attention of everyone I knew. And I thought I knew it all. And what you realize is your knowledge of newspapers and so on is a very superficial knowledge.

Journalism really, really is only the first draft of history. Forty years from now, God knows what we’re gonna know about North Korea and all the other things that are in the newspapers today.

What’s something that was new to you?

The best example is in 1966 when American troops were already fighting in Vietnam. We have a recording in which Defense Secretary Robert McNamara tells Lyndon Johnson the name of the person who is actually the more important person in Hanoi and it’s not Ho Chi Minh, it’s Le Duan. And he spells it for the president who doesn’t seem to be very interested. But it shows you how little even the people in the White House knew about the country they were fighting in.

Were you thinking about current-day lessons from this history while you worked on the show?

I don’t — we don’t — try to ever draw any real parallels. And I don’t believe history really repeats itself. It does rhyme, as Mark Twain [reportedly] said.

But you can’t help thinking how little we know about Afghanistan all these years later.

That’s the thing that is so discouraging, it’s what’s discouraging about Afghanistan, we’ve been there how many years? We’re still not sure of any way out of there. And it’s what happens when you get into places you don’t understand.

What were you doing during this period?

I was married and I had a son and I had polio, so I was never threatened by the draft. [Regarding the anti-war movement], I was marginally involved and had friends who were very deeply involved. But I was married and it was kind of hard — I couldn’t march, so I was not as involved as I sometimes wished I could have been.

Did you have friends serving?

No. I knew no one who served. Which is evidence I think of the class complexities of the draft system.

I was fascinated by seeing the North Vietnamese veterans speaking in the show.

What was astonishing was how frank they are. There was a time when there was such an official view of how they won. It was by rote, sort of. People told us stuff they had not told before, that they’d committed atrocities, that people grew cynical about the sacrifice they were asked to make. All of that is new and it’s intensely human. It’s how people are in wars as opposed to how leaders or ideologues want them to be.

This interview has been condensed. In the interest of full disclosure: I worked for the publishing house that publishes the Ward/Burns books.