Alex Garland Answers the Question: Why Make a Film About Civil War Today?

One of the most haunting moments in Alex Garland’s new drama “Civil War” comes in the form of a question.

A soldier, fingering the trigger of his assault rifle, confronts a group of terrified journalists: “What kind of American are you?” he asks.

That question, and its underlying impulse to divide and demonize, is at the heart of why Garland made a much-anticipated and already much-debated film about the implosion of the United States. “Civil War,” opening Friday, warns against the dangers of extreme partisanship, Garland said in a recent interview — the horrors that can happen when American citizens, or any other group of people, turn on themselves.

“I think civil war is just an extension of a situation,” said Garland, the 53-year-old British director behind “Ex Machina” and “Men.” “That situation is polarization and the lack of limiting forces on polarization.”

In the film, America’s divisions have erupted into chaos. Fleets of helicopters patrol the skies and explosions rock major cities as the secessionist Western Forces, including those from Texas and California, advance on the president, a three-term authoritarian who has disbanded the F.B.I. and launched airstrikes on fellow Americans.

If polarization is one of the poisons causing this outbreak, Garland sees the work of a free, independent press as one of the antidotes. His film envisions the Fourth Estate as a check on extremism and authoritarianism.