Emily Blunt, left, and Tom Cruise in “Edge of Tomorrow.” (David James/Warner Bros. Pictures via Associated Press)

Most of the discussion of “Edge of Tomorrow,” the smart action picture starring Tom Cruise and Emily Blunt that finished third at the box office last weekend to young adult juggernaut “The Fault in Our Stars,” has centered on its central conceit. Tom Cruise’s character Cage, a public relations officer whose job is to sell a war against alien invaders that is going poorly, wakes up in the same day every time he dies. In between the reset function and the menacing so-called Mimics, the comparison to a video game is not unfair.

In the first half of the film, that parallel is a compliment. In the second, as the action sequences get muddied by a dark 3-D print and careless creature design, it is derisive. In either case, “Edge of Tomorrow” deserves to be discussed as an important example of cross-pollination between forms. It is also a sharp little movie about war and politics, from which other politically minded thrillers might take a lesson or two.

The setup for “Edge of Tomorrow” is efficient and nasty. Cage gets called into the office of General Brigham (Brendan Gleeson), whose efforts to beat back the Mimics is going poorly. Cage assumes he is there for a career consultation and has plenty of cynical suggestions for Brigham.

“A best-selling memoir, perhaps?” Cage suggests. “A career in politics?”

Brigham has other ideas. Disgusted by Cage’s cable television appearances and utterly empty rhetoric about how the war is proceeding, Brigham has decided to send him to the front. Cage is near-hysterical when he finds out.

“I do this to avoid doing that,” Cage says, desperate. “I was in ROTC in college, the war broke out, I lost my advertising firm.” It is as if he is Don Draper in reverse, but with no awareness that attempts to get out of duty or fear of combat might be seen as shameful. Cage is a coward and a brat, and he is handed over to a master sergeant (Bill Paxton) who assures him that combat will turn him into a new man.

The film’s politics are, blessedly, not purely left or right. On a personal level, “Edge of Tomorrow” has a somewhat old-fashioned view of masculinity, that a toughening-up will do a weak man good. But on an institutional one, the movie has a view of war that might resonate with liberals frustrated with the wars in Iraq and Afghanistan.

Cage’s private sin is self-interest. His public sin is inducing others to enlist in cause he says is glorious but that he knows is actually a slaughter. When he tells Brigham, “General, I just inspired millions of people to join your army,” his professional crimes magnify his personal ones. If asked, Cage probably could not articulate why he thinks he deserves to be spared combat, while others ought to walk into a meat grinder, but that is precisely what his position amounts to.

“Edge of Tomorrow” resolves both conundrums in a more predictable and less interesting fashion. Cage’s personal redemption is spectacular, ending the war that he shilled for. And the movie never really examines another conundrum it sets up, the intense resentment of a super-soldier named Rita (Emily Blunt). Sold as the “Angel of Verdun” by propagandists for the war, and known by an obscenity by her fellow soldiers, even despite her battlefield prowess, Rita could have been just as interesting as Cage.

We do not get that, and Cage’s political symbolism fades as he becomes a hero. But if you cannot have everything, “Edge of Tomorrow” at least knows how to sketch in a complex political dynamic with swift, deft strokes. Other action franchises might learn from and improve upon that example, rather than trying to pose questions they do not have the courage to answer.

Alyssa Rosenberg blogs about pop culture for The Washington Post's Opinions section.