The attack on the Twin Towers is demonstrably responsible for flipping the fraught relationship between the American public and those who fight their battles for them. Young people may not realize that soldiers in the Vietnam War were widely regarded with the same disapproval that much of society felt toward the war itself. The Woodstock generation didn't support our troops. They weren't even called "our troops" back then.

The dynamic is time-capsuled in the cinema of the period. Coming Home (1978), for example, told the story of a paraplegic returning vet (good guy) who sees the error of his ways, becomes a war protester and wins the heart of a hospital volunteer. She's married to a soldier on active duty (bad guy). When her husband returns from 'Nam, suffering from post traumatic stress disorder, he threatens the couple with a loaded rifle, then takes his own life. Nine Oscar nominations.

Movies made over the next two decades weren't substantially more supportive of our troops. In the '80s, auteurs made Vietnam statement films (Platoon, Casualties of War, Full Metal Jacket). The '90s gave us our first Gulf War glimpses (Courage Under Fire, Three Kings) of what was to come.

While Osama bin Laden was making plans for his attacks, Ridley Scott was making the great transitional war film. Black Hawk Down offered a grueling depiction of a 1993 black op in Somalia gone bad and foregrounded the bravery and brotherhood of its outnumbered heroes. The picture received an Oscar-qualifying release just weeks after 9/11, and the subsequent outpouring of patriotism found an outlet in its pro-soldier narrative. Film historians consider it among the most significant cultural milestones of the young millennium.

Along with a succession of award-winning documentaries critical of Bush-Cheney counterterror policies (Fahrenheit 9/11, Taxi to the Dark Side, No End in Sight), Black Hawk Down played a pivotal role in shifting public disapproval from the American soldier to the American government. That's the lens through which younger audiences have viewed movie war, from Syriana to The Hurt Locker to Green Zone to American Sniper, a film that came close to elevating veteran Chris Kyle to the level of martyred saint. How the pendulum has swung.

That last film was written by Jason Hall, who wrote and makes his directorial debut with Thank You for Your Service, a well-meaning but minor addition to the genre. Miles Teller plays an army sergeant returning home from Iraq in 2007 with three members of his unit. All suffer from PTSD (some things never change).

The film divides its focus between the tensions that Teller's character's troubles cause on the home front — Haley Bennett does subtle work as his caring-but-not-coddling wife — and the failure of the U.S. Department of Veterans Affairs to provide urgently needed treatment. Because the characters are only partial sketches, and neither they nor the film offers commentary on the war, their struggles to adjust to civilian life prove less affecting or informative than they might have. When one of the homecoming soldiers kills himself, the fact goes virtually unmentioned, much less plumbed for meaning.

The movie's sole distinction is the light it shines on the moral hypocrisy of a military that claims to leave no soldier behind yet does the minimum to make its returning soldiers whole again. Talk about adding insult to injury. Despite the contention of our fearless leader, I doubt any of them know they're signing up for that.