Leni Riefenstahl remains a problem to be solved, not because there’s any doubt about who she was, but because we are uncertain as to who we are.

Riefenstahl, a film-maker of exceptional talent, worked assiduously to legitimate and glorify the power of Adolf Hitler, in works such as Triumph of the Will, which raised propaganda to art, and Olympia, a cinematic symphony of sport, which echoed the fascist cult of the body, vigour and eugenics. She survived the end of the Third Reich, living decades longer than the tens of millions of people who died because of Hitler’s genocide against the Jews, his world-consuming wars and his extermination of political opposition, minorities and the marginal. She died in 2003, at the age of 101, still lying shamelessly about her role in one of history’s most evil hours.

She’s back, now the subject of a documentary, Riefenstahl, by Andres Veiel that opened on Friday at the Avalon Theatre in Washington, made with access to new material from the Riefenstahl estate after the 2016 death of her long-time companion Horst Kettner. She is the same monstrosity as she was in 1993, when the three-hour documentary The Wonderful, Horrible Life of Leni Riefenstahl was released; or 2007, when Steven Bach’s biography Leni: The Life and Work of Leni Riefenstahl was published. She lies throughout Veiel’s film, hewing to the practised line that she was an artist not an ideologue, that she didn’t know the extent of the murder and violence, that she was just inexperienced in politics, not a naked careerist. These are the same lies she told on television during the 1960s and 70s, when she worked assiduously to resuscitate her reputation; the same lies peddled in her memoirs.

The film offers a handful of new details on her deceit, including autobiographical notes and recordings, some of which didn’t make it into her autobiography. Veiel paints a possibly more complex psychological picture: an early sexual encounter with a tennis star sounds like rape; her father beat her and once locked her “in a toilet” for 12 hours; her mother was ambitious.

It is an insult to those who have suffered rape or abuse to suggest these details in any way excuse Riefenstahl’s collaboration with evil. Given how often she lied, we can’t even be sure they happened. Nothing Riefenstahl says can be trusted.

What matters about Riefenstahl is her act, the narcissism, the patterns of dissimulation, the sense of victimisation. When the camera catches her in a lie or painful truth, she plays the victim, as if it is rude or ill-mannered for an interlocutor to pursue the facts or point out inconsistencies. She sought publicity and was well-paid for her media appearances.

Veiel’s film uses television clips, scenes and outtakes from interviews and documentaries to anatomise Riefenstahl’s carefully curated public persona. Confronted during a 1976 talk show by a woman who opposed Hitler, a contemporary who saw the truth as it was unfolding, Riefenstahl reverts to a familiar mode: energetic bluster. She filibusters, then she retreats into her shell, like a wounded kitten. No one understands, she says, how difficult it is not to be believed.

That interview led to an outpouring of support from Germans of the same generation. They wrote to and called her, offering thanks and encouragement, sometimes excusing their own blindness and culpability, often sounding nostalgic for the good old days of Nazi moral certainty. For younger viewers, who may think Germany has gone to extremes in its vigilance against fascism, these voices will explain the persistence of neo-Nazi parties like the National Democratic Party (NPD), and the surge of support (including from the Trump administration) for far-right groups such as the Alternative for Germany (AfD).

When we see Riefenstahl in the presence of Hitler, she is radiant. She willingly acknowledges the power of his charisma, but in Ray Muller’s The Wonderful, Horrible Life of Leni Riefenstahl, she qualified that attraction: it was his presence, his power, his mind, not his body, that made her giddy. Appearance is everything for Riefenstahl, especially her own, and she was giddy to the end. We see her stage-managing the lights and camera and shooting angles as she prepares to be interviewed by another film crew, imperious, as always. When she watches her own films, including Triumph of the Will, she is as radiant in their flickering presence as she was in the full sun of Hitler – and equally aware of her own beauty and self-presentation while seemingly absorbed in memory and reflection.

Some of our most successful, or at least most ubiquitous, political figures live in this same perfectly defended solipsism. They don’t experience narcissism as a defect of character but as a kind of fuel, a sustaining operational mode in which there is no past or future, only the present moment with themselves at the centre of attention.

Lies are a dissonance between statement and fact, but it takes time – a reaching into the past – to demonstrate that dissonance. But you said last week … Let’s look at the record … Yesterday, you supported the idea … Ordinary people, when they lie, live in fear of the past coming back to haunt them. The political narcissist lives only in the present where, almost by definition, lies don’t exist so long as there’s another interview, another media hit, another chance to keep spinning, another chance to be radiant before an audience.

Riefenstahl fascinates because our world is still full of courtiers and opportunists who think they can ride the tiger, and just like her, they lie shamelessly, to promote their careers and defend the Leviathan demagogues in whose shadow they flourish. When we once again beat back authoritarianism, will they seem as transparently dishonest as Riefenstahl?

One lesson she taught us, and which this film underscores, is that we must give up any reflexive or simple faith in the camera as a tool of justice. Seeing past crimes doesn’t mean we will punish them. Catching ideologues in a lie doesn’t mean they will reform their thinking. The camera has enormous evidentiary power, but it also has the power to feed our narcissism, our living ever in the present. Very likely, in her mind, Riefensthal outran its power to condemn her acts, her lies, her complicity.

Very likely, in their minds, our demagogues and the people who serve them will outrun justice, too. That leaves their legacy in our hands. We must take notes, hang on to the evidence, write down the facts, never waver in demands for the truth. And pass this all along in hopes that some tribunal of history, some court of public opinion, will note the lies, scorn the liars and consign them to the same rubble and shame left behind by artists like Leni Riefenstahl.