No place on Earth should have more authority to speak about the enduring appeal of democracy than the place that first came up with it. But a new art exhibition in Athens seems reluctant to shout about its credentials. You have to walk right to the end of the National Gallery of Greece’s show, past 137 works by 54 artists, before you come across anything like a claim to authority – and even then it’s far from triumphant. Rika Pana’s paintings of the Parthenon, set against backgrounds of melancholy blue and muddy green, accentuate not the steadfastness of the ultimate symbol of Athenian democracy, but its eventual ruin. In three paintings, from the series The Erosion of Civilisation, the pillars of the temple – commissioned by the radical democratic reformer Pericles in the 5th century BC – look like plumes of black smoke, the uncertainty of its iconic outline emphasising its own perishability. The sombre tone feels timely: Democracy, as the show is called, opens halfway through a year crammed with watershed plebiscites that have an ominously terminal feel and pose uneasy questions. In its liberal representative iteration, democracy may have established itself as the norm of governance in most of Europe, the Americas, large parts of sub-Saharan Africa and Oceania. Yet in countries once considered democratic strongholds, many voters seem tempted to swap it for a version headed by strongman leaders eager to break free from constitutional checks and balances. What happens to democracy when the democrats no longer want it? Appropriately, the show’s curator Syrago Tsiara presents democracy not as a final stage of history etched in stone but as something that was only forcefully wrenched back from the hands of autocratic leaders half a century ago – not just in Greece, but almost simultaneously in Portugal and Spain. Fascism made in 1930s Italy and Germany, along with the autocratic rulers of the Soviet bloc, has such a strong hold on memory that these military dictatorships of southern Europe are often forgotten on the rest of the continent, despite their obvious commonalities. António de Oliveira Salazar, Georgios Papadopoulos and Francisco Franco were all military men, who cracked down on civil liberties and used torture on their enemies, but were Christian traditionalist rather than fascist-revolutionary in their fervour. In the cold war, their strident anti-communism guaranteed them the recognition or direct support of the US, and in Greece and Portugal’s case membership of Nato. Their dictatorships all came to an end within an 18-month period in the mid-1970s, but democracy triumphed in different ways in each country. In Portugal, the turning point came with a military coup in April 1974, while in Spain democracy was restored gradually following Franco’s death in November 1975. In Greece, the junta’s rule unravelled more quickly: student protests triggered internal divisions within Papadopoulos’s circle. Then came a coup in Cyprus followed by Turkey’s invasion of the island, and the seven-year military dictatorship eventually collapsed. To the artists who continued to produce art despite strict censorship, the face of repression in these countries looked remarkably similar. The Athens show has a 1972 sculpture made by Spanish art collective Equipo Crónica, depicting one of the inconspicuous spies of Franco’s secret police, facing an almost identical artwork showing the faceless informants of the Greek surveillance state, produced by artist Yannis Gaïtis at the same time. Symbols of protest were shared: red carnations are not only ubiquitous on the graffiti and protest banners of the peaceful “carnation revolution” captured by Revolução, Ana Hatherly’s 1975 film collage, but also in Greek artist Vlassis Caniaris’s untitled grid of flowers moulded from plaster, made in 1969. Papadopoulos, the military officer who led the coup in 1967 then installed himself as Greece’s prime minister until 1973, used to say his dictatorship was merely “a plaster cast”, there to protect the patient during the “operation” required to repair democracy. Dimitris Alithinos’s sculpture Happening II seems to reference this metaphor, except the patient here is a man strapped on to the roof of a car and suffocating under a sheet of plastic. In the paintings of Nikias Skapinakis, bodies dare to breathe again, naked and unbowed. Democracy, for artists like him, was a physical act of liberation for the entire body politic. The most remarkable pictures in the show are surprising for their choice of artistic style. Pop art is commonly thought of as an Anglo-American genre, celebrating the substance and veneer of consumer culture. Yet for artists such as Spain’s Alberto Solsona and Greece’s Alekos V Levidis, it was the perfect way to expose political violence – even if it was, as the title of the latter’s 1969 monotype on paper has it, “Made in the USA.” Pop art is also the style in which artist Giorgos Ioannou chronicled the events that triggered the junta’s undoing. In November 1973, law students barricaded themselves inside the capital’s Polytechnic university, demanding its removal. The protest scuppered a sham process of liberalisation initiated weeks earlier by dictator Papadopoulos, who brutally cracked down on the occupation. Ioannou’s comic-panel paintings look like a macabre homage to Roy Lichtenstein’s famous Whaam! diptych, only here we see the bullets ripping into the bodies of young people. At least 40 students died during the Polytechnic uprisings, with thousands injured. The diversity of artistic forms on display in Democracy ultimately comes across as a kind of commentary on the overarching theme: that there may well be no such thing as a “democratic” style in art. In fact, in some cases the visual language deployed by some southern European artists to tell the story of their democratic liberation has an oddly anti-egalitarian bent. In National Technical University of Athens, a Marios Vatzias painting from 1975, the protesters who were killed are picked up from the streets by angels and carried to the gods. They are no longer part of the masses but elevated to the few. Martyrdom is a surprisingly common theme, especially in the works of Greek engraver Tassos, whose vision was celebrated in the first show at the National Gallery after the fall of the junta. Freedom fighters here are depicted as ordinary citizens but stylised as archangels toting machine guns, while the executed communist resistance fighter Ilektra Apostolou becomes Jesus on the cross. The show’s opening statement is jarring: the journey towards democracy, the wall panel claims, “begins with identifying the opponent” – which sounds more like a pronouncement from the anti-liberal political theorist Carl Schmitt than a formula for a functioning modern democracy. The street protests that accompanied Portugal and Greece’s shift to democracy are, however, given their rightful place, even if the geopolitical circumstances that made dictatorships brittle enough to be toppled by the demos are largely absent from these artworks – namely the colonial wars that had fatigued the Estado Novo’s armies, the Turkish invasion of Cyprus that undid the junta’s claim to competence, and the rise of the European Economic Community. Societies that suppress freedom of expression, this exhibition contends, are doomed to fall. In this respect at least, art and the interests of democracy align. But that they don’t always overlap should be clear, even if you don’t agree with critic Kenneth Clark, who in his 1945 essay Art and Democracy concluded that art was “incurably aristocratic” in its tendency to exemplify the “rule of the many by the few”. The show starts and ends with Konstantinos Parthenis’s large portrait of Alexandros Papanastiou, whose stint as prime minister in 1924 paved the way for the Second Hellenic Republic. There’s also a small picture, by the same artist, of the goddess Athena’s head, which served as an emblem of the Republican party. But as you walk through the show, these tributes to parliamentary democracy are quickly forgotten. Revolutions make better pictures than institutions. Democracy is at the National Gallery, Athens, until 2 February