Medium Cool is finally so important, and absorbing because of the way Wexler weaves all these elements together. He has made an almost perfect example of the new movie. Because we are so aware this is a movie, It seems more relevant and real than the smooth fictional surface of, say, Midnight Cowboy.

Medium Cool stages, not so much with voguish nihilism, despite its demonstrably downbeat ending, as dispassionate vérité straightforwardness, the growing pains that strain a nation when the countercultural ideal of limitless possibility matures into something closer to political reality.

A film of tremendous visual impact, a kind of cinematic Guernica, a picture of America in the process of exploding into fragmented bits of hostility, suspicion, fear and violence.

So strongly does it challenge the usual commercial film techniques and themes that Hollywood, ever wary both of stylistic innovation and contemporary politics, may never recover. Socially and cinematically, Medium Cool is dynamite.

Medium Cool encapsulates the divisive issues of race and poverty that remain as urgent today as they did in 1968. It also makes us think about the way the media shape our lives and are used to deflect public attention from sustained political action.