During Kurt Waldheim’s Austrian presidential campaign in the spring of 1986, that nation’s collective consciousness experienced a painful return of the repressed, a psychological agony recalled by director Ruth Beckermann in this documentary. Waldheim, who had been UN secretary general from 1972 to 1981, was running for the presidency very largely on the grounds of his international prestige. As far as his war service went, Waldheim had claimed in his autobiography to have been invalided out of (conscripted) military service on sustaining a wound at the eastern front in 1942. But in the febrile few weeks leading up to the election, investigative journalist Hubertus Czernin, together with New York Times reporters and researchers from the World Jewish Congress, discovered documents showing his active membership of the SA, the Nazi Party’s original paramilitary wing, and then his senior rank among the German army’s Group E in Greece and Yugoslavia, where he was, to say the very least, an intimate witness to atrocities.

And so this was a time of agony for Austria, where public opinion was resentful and in some cases openly antisemitic about these outsiders’ criticisms. Waldheim dismissed the accusations and claimed not to remember details. It was also a torment for the international political elite, who had seen Waldheim’s career as a key part of Austria’s postwar rehabilitation as an anti-communist stalwart: Helmut Kohl is shown vehemently defending Waldheim and Ronald Reagan visited a German cemetery at Bitburg that included SS graves – an event parsed at the time as a “gaffe” by the conservative press rather than a deliberate, coded political gesture of reconciliation.

Waldheim won the election but was excluded from entering the US, a distinction he shared with Fidel Castro, and so his presidency was a pyrrhic victory that arguably set the tone for Austrian isolationism to this day. It seems incredible that Waldheim could have got away with concealing his war record for as long as he did. How would he handle the situation now? Undoubtedly, by declaring “fake news” (which he never quite had the effrontery to try) and probably by slyly claiming it was a retaliatory smear due to his sympathy for the Palestine Liberation Organisation while at the UN. An extraordinary, queasy tale.

• The Waldheim Waltz is available on 25 March on True Story.