Ten million people in South Korea, one-fifth of the population, have watched Jang Hoon’s movie A Taxi Driver (Taeksi Woonjunsa) since it was released on 2 August. When I went to see it in Times Square, there were seven of us in the audience. The film is set in May 1980, during the mass democratic uprising – and ensuing military crackdown – in the southwestern city of Gwangju. A German reporter, Jürgen Hinzpeter, was one of the few foreign journalists to witness the events. In the movie, Song Kang-ho plays a cabbie who drives Hinzpeter (played by Thomas Kretschmann) the two hundred miles from Seoul to Gwangju. The story is real, though greased with sentimentality as well as the bbong jjak pop music and fashions of the era.

Throughout the film, Hinzpeter and his driver, whose name he never learns, are on the move. Their pea-green taxi zooms down highways, weaves through military barricades and jostles along country roads. The men run through alleys, chased by plainclothes cops, and help civilians who’ve been shot by state paratroopers. The heroes of the uprising are ordinary people: students, factory workers, nurses, shopkeepers and taxi drivers.

On screen, as in real life, Hinzpeter helps to spread word of the massacre outside Korea. His foreignness is an asset: the military dictatorship censored news of the protests, and blamed ‘North Korean communists’ for inciting violence. In one scene in the film, the owners of a Gwangju newspaper shut down their printing press, pummel defiant staff and hurl galley trays to the floor.

The official version, for decades, was that the state had used limited force in Gwangju, and only against treacherous ‘reds’. Even left-wing presidents maintained that civilian casualties were the isolated work of rogue commanders. The government’s count of the dead has hovered around two hundred, but Lee Jae-eui, who took part in the uprising and later wrote Gwangju Diary (1985), puts the figure at over six hundred, with thousands more injured, arrested and tortured by the police.

What happened in Gwangju was only the most extreme version of what was happening all over South Korea in 1980. In December 1979, President-General Park Chung-hee was killed in a coup d’état. A new military dictator, Chun Doo-hwan, took power and imposed martial law. The violence depicted in A Taxi Driver was part of a systematic state response to the uprising. Recently declassified documents show that the government approved the shooting and bombing of civilians in May 1980, tacitly condoned by the Carter administration. The military deployed paratroopers, armoured vehicles, grenades and machine-guns; fifty rounds of ammunition were allocated for every demonstrator in Gwangju.

Last year, mass street protests called for the impeachment of President Park Geun-hye, Park Chung-hee’s daughter. She was forced out of office in March, in a corruption scandal that took down members of her administration and a chief executive of Samsung. The newly elected president, Moon Jae-in, a former activist and human-rights lawyer, has criticised the Samsung cabal, visited the graves of murdered civilians in Gwangju, and ordered a federal investigation into state wrongdoing – symbolic politics, but welcome all the same.

Moon also campaigned on improving relations with Pyongyang, reprising the Sunshine Policy of previous liberal presidents. But his diplomatic hopes have been limited by the bellicose rhetoric of Donald Trump and Kim Jong-un’s recent displays of force. On Tuesday, North Korea shot a low-flying ballistic missile over Hokkaido, and promised more drills to come. Japan’s conservative prime minister, Shinzo Abe, who has advocated for remilitarising his country, called the launch ‘an unprecedented, serious and grave threat’.

Moon joined Abe in vowing to apply ‘maximum’ pressure on North Korea. His position is delicate: appear weak on the North, and face accusations of communist ties; come on too strong, and lose the left-of-centre support critical to his domestic platform. It’s an ideological snare not only for the president, but for ordinary Koreans too. Restoring the history of the democracy movement reveals the facile politics of red-baiting, and makes room for dissent in its many forms. At a screening of A Taxi Driver in Seoul, Moon sat with Song Kang-ho and Hinzpeter’s widow, Edeltraut Brahmstaedt. ‘The truth of Gwangju has yet to be fully excavated,’ Moon said afterwards. ‘It’s our duty to do so.’