Cover Up: powerful doc on reporter Seymour Hersh chronicles decades of American corruption

Early in Laura Poitras and Mark Obenhaus’s Cover Up, a title card announces that it has taken them 20 years to persuade the Pulitzer-prize winning journalist Seymour Hersh to let them tell his story. Small wonder. Hersh has spent his 65-year career exposing some of the USA’s most horrific secrets, from the 1969 massacre of Vietnamese civilians at My Lai by the US Army, to the CIA’s Operation Chaos, a massive programme of domestic espionage aimed at undermining anti-war efforts, to the terrible, indelible images of torture at Abu Ghraib in the early 2000s. It’s a miracle in many ways that he’s survived this far. Naturally, he’s unsure who to trust and fiercely protective of his sources. At one point, he threatens to abandon the project altogether. “This is all supposed to be after death,” he barks at Poitras, who gently talks him down.

Poitras and Obenhaus have quite a job on their hands. Hersh – Sy to his friends – is a spiky, evasive subject, who protests (perhaps a little too much) that he doesn’t like talking about himself. It’s a journalist’s job, he tells the directors, to “get out of the way of the story”. Who cares about his childhood or motivations, his personal life or the toll the atrocities he has exposed might have taken on him? Of course we do, and it’s to Poitras’s credit as an interviewer that she manages to glean the odd, tantalising insight. Hersh’s Lithuanian immigrant father never spoke to him of the Holocaust; his mother, he says, was a chronic liar. His wife – of all things – is a psychoanalyst, and one senses the key to his sanity.

For all his combativeness (colleagues describe a volatile man, prone to screaming and threats) Hersh has a certain charm. A cranky pressman of a type that used to be played by Cary Grant or Burt Lancaster, he talks in bullet points and is given to using old-timey phrases such as ‘moxie’ and ‘pizzazz’; calls one informant “baby” and refers to incendiary revelations as “dynamite”. Unsurprisingly, Cover Up is drenched in nostalgia for an analogue era of journalism. This is a film that clings to the credibility of the image (“No photographs, no story,” Hersh barks) and lingers over the teetering piles of box files that line Hersh’s home office; the yellowed contact cards in his Rolodex; his typewritten notes, overlaid with scratchy ballpoint corrections, and, most stomach-churningly, annotated maps of My Lai on which the words “Ate lunch” sit adjacent to “Dead baby”. Poitras and Obenhaus splice in grainy footage of television interviews and stills of the New York Times offices. Hersh’s contribution to the unfolding Watergate scandal is unpacked, Bob Woodward fondly recalling a friendly competition to get the latest scoop. Here is CIA chief James Angleton resigning; Kissinger capitulating; Nixon grousing that while Hersh is a “son a bitch, he’s usually right”. Squint hard enough and you can just about believe in the power of journalism to win justice.

But of course, that’s only half the story, and as the examples of corruption pile one on top of another a different picture emerges. Cover Up begins as a more-or-less straightforward historical documentary, asking us to look again at a dreadful chapter in history that for many viewers will be most familiar from its fictional retellings, in films like Platoon (1986) and Apocalypse Now (1979), yes, but also Forrest Gump (1994), the scope of whose story bears a strange, twisted similarity to Hersh’s. Gradually, though, the loosely chronological structure begins to splinter. From My Lai, we scuttle backwards to 1940s Europe and forwards to contemporary Gaza, passing the assassination and installation of Chilean leaders on the way. To paraphrase one of Hersh’s sources, the past, present and future collapse into one another.

Over the course of 117 minutes, the corruption at the heart of America reveals itself as many-headed hydra. “We’re a culture of enormous violence,” Hersh laments. And as importantly, “a culture of denial”. It’s hardly news these days that the scandal goes all the way to the top; nor that evil can be a banal, everyday thing, stumbled across on a loaned laptop by a suburban housewife. The question is why so many continue to turn a blind eye. A brief foray through Hersh’s late career suggests that he is not without his failings. Still, one can only stand in awe of his dogged determination to reveal a history that is, as he remarks with typical understatement, “so hard to write”.

► Cover-Up is in UK cinemas now.