The Tomorrow War plainly states that Dan Forester's (Chris Pratt) future is pretty dark, but one detail proves that it's even darker than he may realize. The Dan of present-day is an Iraq War veteran, biology teacher, and devoted husband and father. But when the movie flashes through Dan's documents, one in particular sticks out — a legal document related to a domestic violence charge against Dan by his wife Emmy (Betty Gilpin).
In the year 2022, a group of time travelers arrives with a dark message. They inform the characters in The Tomorrow War that in 30 years, mankind is losing a war against an alien enemy. They're on the brink of human extinction, so they decide to travel back in time to recruit citizens to help fight in the war. Dan is drafted for a seven-day term of service. Once he's jumped into the future, he reports to a Colonel Forester (Yvonne Strahovski), who happens to be his daughter, Muri, in the future. She's initially reserved, but eventually shares with her dad the future dark path he goes down during her childhood.
That dark path is familiar to Dan, as it's the same one his father, James (J.K. Simmons), also went down years earlier. That domestic violence document proves Dan's future is darker than he realizes, as it reflects his father's past. No matter how hard Dan tried not to be like his father, and no matter how much he resented his father for what he'd done, in the future, things still come full circle and Dan ends up in the exact same violent, depressed place. It's just added weight to show how important the central mission in The Tomorrow War is to saving Dan's life, not just literally but emotionally.
Early in The Tomorrow War, it's revealed that Dan's dad walked out on him during his childhood. As expected, it had a profound effect on Dan; though he shares a name with James, he chooses to go by his middle name to further separate them. James finally explains to Dan that when he came back from the Vietnam War, he wasn't the same man. Angry, violent, he wasn't himself and he couldn't find a way to let go of the fury. So he did the only thing he could do, and left, telling Dan, "You've been mad at me your whole life because I left you. But I'm telling you, it would've been worse, for you and your mom, if I'd have stayed."
Dan is shown having a positive and loving relationship with Emmy and his daughter Muri; it's understood that he worked hard to give his family the life he and his mother did not have when he was growing up. But the domestic assault charge document reveals the heartbreaking irony of Dan's future: He also turned angry and abusive, but, unlike his dad, he was determined to stay and it ultimately made things worse for his family. In the end, the father he had spent his entire life hating had been right all along. The domestic violence document proves that Dan's projected Tomorrow War future ends up even darker than James's, culminating in his death.
It's a vicious cycle. Dan knows the devastating impact his future actions have on Muri as he experienced it with his own father. But the events of The Tomorrow War allow him to see how easy it is to fall into the dark place that his father went to. It's what gives him the motivation by The Tomorrow War's ending to forgive his father. The missions to the future and to Siberia were brutal, but the empathy he gained from experiencing a similar journey to his father The Tomorrow War was the only way to protect his family and ensure he didn't turn into the man he glimpsed in the future.
