What This Is Us Gets Right and Wrong About the Vietnam War, According to an Expert

This article contains spoilers about season three of This Is Us.

After two seasons of secrecy about the past of patriarch Jack Pearson (Milo Ventomiglia), This Is Us has opened the door into the elusive war hero’s background. The third season was marketed as a deeper foray into his experiences in the Vietnam War — and in the first third of that season, the show has already made good on that promise by revealing some very specific and shocking details.

Elizabeth Berger, co-showrunner and executive producer, told Vulture that This Is Us tapped Tim O’Brien, author of Vietnam novel The Things They Carried, to consult on the Vietnam story line this season and help the team of mostly young writers craft a compelling — and accurate — narrative. The show is still fiction, though, so just how realistic is it?

TIME spoke to Stephen Maxner, the director of the Vietnam Center and Archive at Texas Tech University, to find out what the makers of This Is Us get right — and wrong — in their depiction of one of the most devastating and divisive wars in American history.

Could Jack have enlisted even if he wasn’t eligible for the draft?

It’s impossible to discuss the Vietnam War without getting into the draft lottery. When the war began, the United States depended on the selective service draft. In that system, all eligible men had to register when they turned 18 and had the potential for being called on to serve. But, while the draft was compulsory in theory, there were lots of ways to get out of it. Many men were exempted from serving due to having a job that was deemed “important” or by being a university student; the majority of the non-exempted men were minorities or had lower incomes.

But, Maxner explains, it soon became clear that a new system would be needed. In 1969, the government launched a new system of drawing names from a lottery, in an effort to get more troops on the ground.

On This Is Us, Jack Pearson’s irregular heartbeat exempts him from serving. But his brother, Nick (Michael Angarano), had no such luck when his birthday was drawn from the lottery. Jack ends up in Vietnam after enlisting in the war to join his brother.

Maxner says it’s feasible that Jack would have gotten past the medical examinations, as those tests weren’t actually very advanced or complicated. For an issue like an irregular heartbeat, it may have been easy to sneak through; and Jack’s doctor’s advice — to do push-ups before going in for the army physical — could have worked in real life. And it’s also not so crazy that Jack wanted to enlist, either. Many men who were eligible for the draft would try and make deals with recruiters to get good deals on their service rather than wait around to see if they’d be called upon.

“They’re trying to have as much control over their fate and destiny as possible,” Maxner tells TIME.

Are the combat scenes realistic?

This Is Us has very clearly depicted the guerrilla combat that really was the dominant tactic at use in Vietnam. But, the visuals of these combat scenes are perhaps the least accurate aspect of the show’s Vietnam moments, according to Maxner, who says the soldiers’ costumes and props on the show do not particularly resemble those in reality. “The uniforms, the equipment, the way the soldiers look in the field: it doesn’t ring true,” he says.

Another issue with This Is Us‘ wartime fighting scenes — mostly during the season’s fourth episode, simply titled “Vietnam” — is the way Jack and his platoon make use of obvious and clearly carved paths through the woods. The use of such a trail results in Jack’s friend (who returns in later episodes as Charlie Robinson, an older man who gives wisdom to Jack’s lost son Kevin) losing a leg, which could have been avoided. “That was a big no-no,” Maxner says. “Unless you wanted to be engaged — and you wanted to potentially get shot — you just didn’t use trails. That was kind of far-fetched.”

There was also another moment that could have alerted the Vietnamese to the soldiers’ whereabouts: the fact that the guys were playing football.

According to the show’s timeline, that fighting scene occurred in 1971, at least six years after American soldiers began fighting on the ground in Vietnam. Maxner says that by 1971, this kind of activity would be unlikely to have happened, because the American goal was to minimize casualties as efficiently as possible.

“That’s pretty late in the war for soldiers to be conducting themselves like they don’t know what they’re doing,” he says.

However, the way the soldiers patrolled the base, as well as some of the silent hand motions they used as signals, were accurate depictions of such wartime moments, Maxner says.

What would interactions with Vietnamese civilians have really been like?

During one scene in the episode “Vietnam,” a Vietnamese boy hands Jack a fish that he caught. At first, Jack is very kind to the boy — whose mother Jack might have had a relationship with, viewers learn — but then another soldier becomes quite angry, warning Jack not to communicate with the Vietnamese and yelling at the boy and his mother to go away.

This scene was a “great depiction,” Maxner says, of the challenges faced by Americans occupying space in Vietnamese communities. “You had some Americans who were sympathetic to the situation and wanted to have a positive relationship with the civilian population, and then you had those who didn’t care, who were angry.”

Inevitably, individual soldiers’ experiences with the war had direct effects on how they interacted with the Vietnamese. It’s possible that the angry soldier — who thought they couldn’t trust this little boy to give them food — had just lost a friend in a battle, Maxner says. But Vietnamese civilians were just as affected by the fighting as the American soldiers were, so the dichotomy of sympathy and anger existed in their communities, too. “That happened on both sides,” Maxner says.

Is it feasible that Jack’s military service would have been so mysterious to his family?

Though the depictions of the war may not be perfectly accurate, Maxner says, This Is Us aces its depiction of life after the war.

Jack not only hid details about his time in Vietnam from his family, but he lied about his position, claiming he was “just a mechanic” and didn’t see combat. His son is later shocked to learn the truth about his father’s important role in the war, and confused by his father’s lack of candor.

“In my experience, with this particular war, the answers are so dark — you’re better off not having them,” his father’s friend explains to him.

In this quote lies a core truth about many veterans‘ experiences after the Vietnam War, Maxner says. When troops came home, they were not only faced with the challenges all veterans face of reintegrating into civilian society, but also with something much darker.

“They came home to a nation that was ambivalent at best and hostile at worst,” Maxner says.

Post-traumatic stress disorder (PTSD) was not recognized as a disorder until years after Jack Pearson and every real American soldier returned from Vietnam; it wasn’t until 1980, five years after the war was officially over, that the disorder was added to the DSM. Maxner says it was common for soldiers to self-medicate with drugs and alcohol, as Jack Pearson did for years before overcoming alcoholism. When Maxner and the faculty at the Vietnam Center conducted a series of interviews with Vietnam veterans in 2000 for an oral history project, Maxner says many told the researchers it was the first time they had ever opened up about the war — 20 years later.

“They didn’t talk to their wives, their parents, their kids. They didn’t talk to anybody about it,” Maxner says. “They experienced some incredibly difficult and dark things, and they didn’t want to relive it. They didn’t want to talk about it.”

Maxner hopes that This Is Us will use its platform to continue using this Vietnam story arc to educate Americans, and hopefully create a better country to which veterans return home.

“It really is a great mechanism that they’re introducing,” he says, “where they can remind Americans of what veterans experience and how it affects them when they get home.”