Viggo Mortensen is late. Very late for an interview.

It’s an hour and a half past the appointed time, but when the actor finally calls, he has a very good excuse.

“It was a veterinary emergency,” he explains, apologizing profusely. It seems that his dog recently had an operation and the stitches were “wobbly,” requiring an emergency touchup.

This is the domestic Mortensen. A retiring, but passionate artist, who has chosen to live his life away from the public glare. On screen, he remains unknowable. For over two decades, Mortensen has captivated audiences with his intense performances in a wide variety of roles, no part like the other. He was a swashbuckling Aragorn in “The Lord of the Rings,” a steely Russian mobster in “Eastern Promises,” and a remote and cerebral Sigmund Freud in “A Dangerous Method.” In his latest film, “Captain Fantastic,” which screens Tuesday at Cannes, Mortensen transforms himself again as a hippie father who attempts to reintegrate his family into society after living off the grid.

“This is a movie of this time,” said Mortensen. “It’s not about progressives being right or that you’re an idiot if you’re conservative. It’s that we can all be heroes and villains at different times.”

The film, Mortensen argues, is in many ways a plea for both sides of the political divide to continue to engage with and listen to one another. That might be difficult, he notes, in the case of presumptive Republican presidential nominee Donald Trump.

“This thing is like the Roman Colosseum,” said Mortensen. “They cheer when Trump baits people. He never backs down or apologizes. In fact he makes a show of not apologizing, and yet he’s touched a nerve of anger.”

Mortensen supports Bernie Sanders, calling Hillary Clinton, his Democratic challenger, a “moderate Republican.” The actor lives abroad in Spain, but says he remains interested in the presidential election, and believes that his geographic remove gives him a unique perspective.

“People look at the U.S. foreign policy and worry about it throwing its weight around,” he said. “They wonder how hardcore the next president will be. Bernie is not shy about voting for military appropriations, but I feel safer with him than with Clinton or Trump.”

Beyond politics, Mortensen suggested that after years of scrambling to cobble together financing for his films, David Cronenberg, his collaborator on the likes of “A History of Violence” and “Eastern Promises,” may hang up his movie camera. The director has told the actor he’s getting more pleasure from writing novels.

“I can’t think of another around that long that stays as fresh,” said Mortensen. “It’s ridiculous. Woody Allen makes a movie every year and other directors make whatever they want to. Here’s one of our greatest directors and he has so much trouble getting his movies made.”