Any cinephile old enough to go to the movies habitually in 1996 will remember the trailer for that year’s biggest hit, the fun-but-dumb-as-dirt UFO invasion throwback Independence Day. Its trailer ran before every movie I saw for half a year, culminating in a shot of the White House being vaporized by an alien death ray. The audience laughed and cheered, every time. Destroying the White House seemed like a harmless gag to put in a popcorn movie way back then, during what poly-sci guy Francis Fukuyama called the End of History. 

Alex Garland, who wrote the sublime genre flicks 28 Days Later and Sunshine for Danny Boyle before making his directorial debut with the astonishing Ex Machina, is an substantially more ambitious and curious filmmaker than Independence Day’s Roland Emmerich. His latest provocation, Civil War, is an astonishing feat of purely cinematic storytelling—terse, tense, observant, persuasive, and maybe even irresponsible. The film’s final section depicts a room-by-room assault on the White House by soldiers of the Western Forces, an unlikely union of breakaway states Texas and California against a federal government that has already put down rebellions by “The Florida Alliance” and other strange bedfellows. Nothing about it is funny. I’m not sure it’s harmless, either.

My reservations about Civil War are confined to its militiaman-fever-dream finale; Garland’s terrifying evocation of a chaotic post-United States doesn’t put a foot wrong for its first two acts.

Our guides through this terrifying landscape are three generations of war correspondents: Kirsten Dunst is note-perfect as the 40-something Lee Smith, a photographer on assignment for Reuters along with adrenaline-addled reporter Joel (Wagner Moura). At a Manhattan hotel bar where journos attempt to drink themselves to sleep after witnessing the suicide bombing of a water-distribution truck—this is, have I mentioned, a dire film—the pair hook up with Sammy (Stephen McKinley Henderson), an old hand from “whatever’s left of the New York Times,” and Jessie (Cailee Spaeny), an aspiring photojournalist who idolizes Lee. But it’s Joel, not Lee, whom Jessie persuades to let her join their quest to D.C. to interview the President before the closing-in Western Forces depose him. 

Because I-95 is now a cratered memory, the trip “down” to D.C. becomes an 850-mile counterclockwise swing through the two-lane blacktops of Pennsylvania and West Virginia. This is a war movie and a road movie. Our fearsome foursome encounter threats and atrocities as frequently as rest stops, and occasionally at rest stops. In one surreal set piece, a Christmas carnival, its Muzak loop of holiday carols still blaring across the tall grass in the middle of summer, turns out to be a battleground between two snipers. Neither one knows who they’re shooting at or what their politics may once have been. It’s just the Law of the Jungle asserting itself, and the fact that the one shooter we hear from seems fully conscious of and annoyed by the brutal absurdity of the situation amplifies the tragedy. Animals don’t know they’ve fallen from grace.

That scene encapsulates Garland’s big decision to elide the basis or history of the conflict. We don’t know how long ago the shooting started or who fired first. All we get in terms of specificity is that President (Nick Offerman, he’s never given a movie name; he’s just POTUS) is in his third term, he’s dissolved the FBI, and ordered airstrikes on U.S. cities. Garland’s point, that the barbarism and terror of war immolates any claim to moral or ideological purity, is well-taken. The gun battles he stages aren’t titillating, they’re terrifying. Like anyone in a war zone, we just want the bullets to stop.

The sanctity of an independent press seems to be key to whatever argument Garland is making, but fake news and discord-amplifying social media channels aren’t really addressed. (Cellular networks are as unreliable as freeways or U.S. dollar in this world.) A certain segment of the audience for Civil War—which went into production a little more than a year after the Jan. 6 riot—will likely receive it as an indictment of the journalists who stand over a wounded soldier and click away as he bleeds out. And under different circumstances, I might say Garland isn’t responsible for what elements the most bloody-minded audiences take away from his imaginative work. 

But his scrupulous both-sidesism crumbles in the face of a few inescapable facts: There’s only one political party in the United States that has championed a president who refused to leave office after losing reelection. There’s only one party whose leader has called journalists enemies of the people. And there’s only one political party that has advanced the suicidal notion that assault rifles should be readily available to anyone, no background check or proof of competence required, and that these mass shooters in waiting should be free to carry their weapons openly in public places. 

At one point, Dunst’s Lee remarks to Henderson’s Sammy that she’d hoped in vain her photos from other conflict zones might deter her homeland from following down that self-destructive path. Garland’s vivid, urgent, cautionary tale will be just as ineffectual, I fear. Civil War’s performances are uniformly excellent. Rob Hardy’s cinematography and Jake Roberts’ editing are excellent. Garland made a brilliant film. I wish that he had not.

Civil War (R, 109 minutes) opens in area theaters today, April 12.