“Civil War,” the new film from Alex Garland (“Ex Machina,” “Annihilation”), is a deeply disturbing movie. Primarily a road trip through a devastated Eastern United States by a group of journalists, it shows what an American civil conflict might be like. The picture’s slower moments are juxtaposed against extreme levels of violence as the war rages on. The net effect is disorientation, fear, and a stark realization that it could happen here.

It is never clear why the Western Forces (WF) in Texas and California left the United States. What is disclosed through dialogue is that the current U.S. President is in his third term, has abolished the FBI, and seems to have attacked his own citizens. The WF has besieged the District of Columbia and seems on the verge of success.

The film opens with the President (Nick Offerman) practicing a speech in which he claims a major victory against the WF. As later developments make clear, this is a sham gesture.

Lee (Kirsten Dunst), a photojournalist, and her colleague reporter Joel (Wagner Moura) arrive at a protest in Brooklyn in a van marked “Press.” Why the police and the crowd are in a standoff near a petroleum tanker is never made clear. Someone throws an incendiary device which causes a major explosion. Lee saves Jesse (Cailee Spaeny), an aspiring photojournalist.

Later at a hotel, Lee and Joel reveal to veteran reporter Sammy (Stephen McKinley Henderson) that they are going to go cross-country via a circuitous route to get to D.C. They want an interview with the President before the WF capture Washington.

Sammy warns them that they will be shot on sight. Nevertheless, Sammy wants to come along to get to Charlottesville, VA, where the WF are encamped. Lee is not thrilled, due to his age, to have him along as a passenger.

Jessie meets Lee as she prepares to go to her room. She formally introduces herself and makes clear her aspirations to become another Lee, a legend in journalism circles.

The next morning Lee goes down to the van to find both Jessie and Sam sitting in the passenger seats. She argues with Joel about it but it is a fait accompli.

As they travel through Pennsylvania, we see the devastation on the highways in the form of abandoned or bombed-out vehicles. Random buildings are on fire from who knows what cause.

They arrive at a gas station for fuel. Three scruffy-looking, ominous figures with guns are there. They agree to provide provisions for Canadian money (!).

The youngest one takes Jessie, later joined by Lee, behind the building where two badly-beaten men are strung up and still alive. In a macabre scene, both photojournalists take pictures of the men while doing nothing to help them.

Farther down the road, they encounter local men in plainclothes fighting men in fatigues. It is not clear if the men in plainclothes are a local militia or not. Also unclear is the identity of the uniformed men: are they U.S. or WF? Again more pictures are snapped, with the stills freezing the frame of the movie for a moment with each shot. This is just the beginning of a much bloodier journey as the quartet continue their long journey to Charlottesville and D.C.

“Civil War” provides a reified example of what a U.S. Civil War, which I fear happening, would look like. So in one way, the movie is a warning shot to Americans to see what could be the consequences of our actions. Of course, I worry about unstable people using this as a call-to-arms for a revolution. But for most of us it should be a sobering moment.

One of the themes that occurs in this film is the role of the photojournalist and reporters in a war zone. In theory they are neutral players, although by their very appearance on the scene they alter the dynamics. Watching Lee and Jessie snap photos of the two men at the gas station while never trying to help them is part of their ethical code as observers only. But as a human being, you can’t help but be appalled at their non-intervention.

This is one of the many brilliant ways in which director Alex Garland makes his audience uneasy. He asks the messy questions for which there are no clear answers.

The use of the freeze frame as photos are snapped is worth noting in particular. Each frame so depicted could be the next still photo we see in the coverage of a war. But as viewers we rarely think about the context in which such photos are taken.

The violence, when it occurs, is absolutely intense. You feel like you are there. The sound effects are loud and enveloping. The sheer volume of blood and dead bodies as the journalists progress in battle scenes is shown at ground level. This picture ends up being an anti-war story as a result.

Kirsten Dunst as Lee gives the performance of her life. She showed her chops in “The Power of the Dog,” but here she goes to another level. Her ennui and disengagement with life in pursuit of her goal of getting the next big photo is subtly presented. Even when she goes into PTSD after a harrowing, near-fatal encounter for the group, she shows the confusion and fear well.

The other acting kudo I have goes to Stephen McKinley Henderson in the role of Sammy. He provides a nice counterbalance to the hard-nosed Lee. He recognizes the limits of his profession. While he is jaded, he is not so far gone that he has stopped being human.

The final shot of the film is one of the scariest endings I have ever seen. When I was a child, I used to be afraid of fictional monsters. Then, as an adult, I realized that what I needed to fear were other people who were monsters. That is why I say that the scariest book I have ever read is “The Handmaid’s Tale,” another story that could easily become reality.

“Civil War” is a masterpiece. It is not suitable for any children or tweens.

Five out of five stars

From filmmaker Alex Garland comes a journey across a dystopian future America, following a team of military-embedded journalists as they race against time to reach DC before rebel factions descend upon the White House.

STARRING Kirsten Dunst, Wagner Moura, Cailee Spaeny, Stephen McKinley Henderson, Sonoya Mizuno and Nick Offerman
WRITTEN & DIRECTED BY Alex Garland