Rennie Davis had come to protest peacefully. The police had come to riot. Wielding batons, they stormed forward yelling, “Kill Davis!” he recalls. He was cracked on the head, knocked to the ground and felt lucky to escape with his life.

It could be a scene from this year’s summer of civil unrest in America. In fact it was a demonstration outside the 1968 Democratic national convention in Chicago that descended into a violent clash with police and the national guard.

The story of Davis and other organisers of the protest is told in The Trial Of The Chicago 7, a film written and directed by Aaron Sorkin that premieres on Netflix on 16 October. Its star-studded cast includes Sacha Baron Cohen, Joseph Gordon-Levitt, Michael Keaton, Frank Langella, Eddie Redmayne and Mark Rylance.

In an interview with the Guardian, Davis, 80, says he was not consulted during production of the film and expresses serious reservations about how he and fellow activists are portrayed. But he also welcomes the timeliness of its release.

“Coming out at this time is just really perfection,” he says by phone from his home near Boulder, Colorado. “There are some things that I wouldn’t agree with how Sorkin has characterised certain figures in the trial, myself included. But the impact of the movie is there and I certainly endorse and support it.”

The tumult of 2020 – a global pandemic, economic crisis, an uprising over racial injustice – has frequently been compared to 1968, when the Vietnam war was raging, Martin Luther King and Robert Kennedy were assassinated and major cities were engulfed by violence.

From a farm community in Michigan, Davis’s political awakening came in the early 60s. He helped created Students for a Democratic Society, effectively the voice for students in the north. Davis was an activist and community organiser and joined the antiwar movement in around 1965.