Last Monday Matteo Renzi, Italy’s former prime minister, announced, as results of the general election still rolled in, that he is resigning as leader of his country’s main left party, the Partito Democratico (PD).

He is leaving, but not just yet. Just one more battle. He is determined that his party, as some wish, does not prop up a government led by the populist Five Star Movement.

In 2016 Renzi staked his career on a disastrous referendum on electoral reform, and lost. He resigned as prime minister, passing the baton to colleague Paolo Gentiloni, but fought to return in the election last weekend .

This too was a disaster. The former darling of European social democrats, seen as a new Tony Blair, a moderniser with a flair for the cameras, led his party to a crushing defeat last weekend. The PD’s national vote halved compared to 2014, down to 19 per cent.

Renzi and his party are the latest victims of the meltdown of centrist European social democracy

Matteo Renzi: he resigned as leader of the Democratic Party after winning only 19.1 per cent in the Italian election. Photograph: Elisabetta Villa/Getty

It’s not all his fault. Although that will be little consolation.

Renzi and his party are the latest victims of the meltdown of centrist European social democracy, the mass workers’ parties which led Europe in the postwar years and defined its welfare state and social partnership economic and political model.

It is a shift in Europe’s political tectonic plates as significant as the remorseless rise of populism. The eclipsing, perhaps permanently, of one of the pillars of a collapsing power duopoly – with the Christian democrats – at the heart of governments across the bloc and the EU’s institutions.

And it is “not only the crisis of social democracy we are experiencing, but that of the compromise-based postwar political model in Europe,” argues Norwegian union adviser Asbjørn Wahl.

Like it or not the consensus politics of the postwar years are coming to an end, surviving perhaps only in the renewed, weakened German coalition of Angela Merkel and the Social Democrats (SPD). The changing times are manifest in the previously taboo willingness of politicians to bring far-right, sometimes openly fascist parties, into governments from Austria to Greece to Finland.

Ireland is not unaffected by the tide

In 2000, social democrats or socialists were part of the government in 10 out of the 15 countries that made up the European Union at the time.

Today, following crushing defeats for the left in France, Holland, Germany, Austria and the Czech Republic, among others, only six EU governments out of 28 member state governments, most of them on the European periphery – Malta, Portugal, Romania, Sweden, Slovakia and Germany – have social democrats in their ranks.

‘Existential’ moment

Ireland is not unaffected by the tide. Labour crashed in 2016 from a historic high of 37 to seven seats. It faces, as former leader Ruairi Quinn admits, “an existential” moment.

France’s Socialist Party won just 6.4 per cent in the presidential vote and 9.5 per cent in the parliamentary election last year, and Greek social democratic party Pasok last polled at just over 6 per cent, yet both ruled on their own in recent years. There is even a new word for the social democratic collapse: “Pasokisation”.

In the Netherlands Labour (PvDA) has also been a regular central part of governing coalitions – but it took only 5.7 per cent at the last election. In Belgium, due to go to the polls in May 2019, corruption scandals are draining support from the once-dominant francophone Socialists of Wallonia. Their Dutch-speaking comrades in Flanders hope to reverse their own slide by ridding their party of its old-guard leaders.

In Germany – the birthplace in the 19th century of social democracy – although the SPD hasn’t led the government since 1998 when it took more than 40 per cent of the vote, in September it won just 20.5 per cent.

The social democrat vote has been peeling away to left and right. In Spain the Socialist Workers’ Party (PSOE) is languishing, polls suggest, on around 20 per cent, having lost voters to the left to the Podemos movement, originally an anti-globalisation movement, and to Ciudadanos on its right, a centrist party that many voters feel is better able to hold the ruling Partido Popular to account over the many corruption scandals it is implicated in.

In Greece the hard-left Syriza alliance has pushed Pasok to the brink of oblivion.

In Ireland a combination of hard-left parties, a new Social Democrat party, and the more populist Sinn Féin have squeezed Labour.

Much of the social democratic left’s leadership, however, also accepted the arguments of Tony Blair

In France and Germany the PS and SPD respectively have faced rising challenges from a former member Jean Luc Melenchon’s France Unbowed and the formerly communist Die Linke.

All such challengers have benefited from angry voters’ sense – right or wrong – that social democratic parties have become part of the establishment, enforcers of austerity politics. Usually that has been rationalised by leaders as their attempt to put manners on otherwise unconstrained conservative partners.

Quinn says of Labour’s participation in the post-crisis government of 2011, that party members “wanted change, not rhetoric” and that “social democrats are about dealing with the real world”.

Jack O’Connor, Siptu’s outgoing president, admits that social democracy has paid a heavy price for holding such positions. Speaking at a commemoration of Jim Larkin last year he admitted social democracy has been “severely discredited”.

It “has burned a huge amount of its political capital in a desperate effort to mitigate the austerity agenda by participating in governments dominated by the centre-right, and has consequently ended up being blamed for a collapse that was not of its making”, he said.

“Others, on an increasingly fragmented left, seem content to be defined by reference only to what they are against rather than offering a vision of what they are for, or how it would work,” he added.

Yet the moral high ground is not enough to be re-elected, and the argument was lost on many supporters. Or the “difficult choices”not properly explained, Quinn accepts. It’s a difficult message as parties throughout Europe found.

Much of the social democratic left’s leadership, however, also accepted the arguments of Tony Blair and his international adherents of the “Third Way”, that globalisation of markets and the financial crisis no longer left socialists the room for manoeuvre they had in the past. Keynesian economics, they argued, was dead.

But what was left, critics said, was technocratic managerialism. It might be “necessary”, but it was never going to win voters over if it meant inflicting pain on them.

In Germany, Gerhardt Schröder’s “Agenda 2010”, a set of reforms that pared back many of the social protections and benefits Germans had come to take for granted, deeply divided the party and cost it the 2005 election.

“The SPD never overcame the trauma of the Agenda 2010,” Albrecht von Lucke, a German political scientist and author told Der Spiegel.

Grand coalition

“People don’t see any major differences between the big parties anymore,” argues Kevin Kuehnert, the leader of the SPD’s youth wing Jusos, who tried unsuccessfully to defeat another grand coalition with Merkel.

“All the parties are pro-European, a bit for protecting the environment and somehow for the status quo,” he says. “Where’s the hard profile?”

Quinn argues that social atomisation, the disappearance of the many bonds that once united people has undermined the psychological base of these traditional mass parties

One party that has bucked the trend is Britain’s Labour Party, precisely by adopting such a “hard profile”.

Until the 2017 general election, Labour too was displaying symptoms of “Pasokification”, but a sharp swing to the left under Jeremy Corbyn and a firm distancing from Labour’s own past allowed it to defy the conventional wisdom that insists left-wing ideas are a turn-off to voters, and to achieve the largest increase in the party’s vote since 1945 and its highest share, at 40 per cent, since 2001.

Corbyn was undoubtedly helped by a UK electoral system that makes the emergence of new parties particularly difficult – left-wingers had no choice but to concentrate their efforts on capturing the party from social democrats rather than replacing it, and voters were offered no realistic choice but to vote Labour if they wanted to be effective in opposing Tory policies, not least on Europe.

But the Corbyn revolution revealed important other realities. The voting base was shifting. Like elsewhere, new forms of industry meant the old manufacturing and trade union base of the party was dying off or turning to new forms of identity politics such as Ukip. Labour was having to find new supporters elsewhere – Corbyn’s revival of its fortunes was on distinctly new ground for social democracy.

Quinn argues that social atomisation, the disappearance of the many bonds that once united people – communities, families, trade unions, churches, clubs, and sporting organisations – has undermined the psychological base of these traditional mass parties.

And class is no longer a great predictor of voting intention, as British Labour got virtually the same vote share among each social class. That was useful in improving its position by 7 per cent with the professional middle classes since its 1997 landslide, but the party was 15 per cent down with the poorest, and 10 per cent down with the next poorest groups since then, despite only a 4 per cent drop in its total vote share.

Breaking the cycle

Another party breaking out of the cycle of decline is the Danish Labour Party, although in a sharply different direction.

Leader Mette Frederiksen has shocked many in her party by moving onto the same turf as the anti-immigrant, far-right Danish People’s Party. It is an acknowledgment that many of her party’s voters, like former social democrats throughout Europe, have succumbed to the lure of the right’s anti-immigrant rhetoric and identity politics.

Mette Frederiksen, leader of the Danish Socialists Party: she has shocked many in her party by calling for curbs on migration and for asylum seekers to be lodged in migrant camps run by the UN in north Africa. Photograph: Liselotte Sabroe/AFP/Getty

Frederiksen has called for curbs on all migration to Denmark and for asylum seekers to be lodged in migrant camps run by the UN in north Africa, where their claims could be assessed.

She sees the social democrats’ failure to take up the immigration issue as a gift to the far-right. “If social democrats,” she says, “are unable to appeal to those who are most strongly affected by the challenges of the future and the changes in our society, we are not a true social democratic party.” She believes the same applies to other social democrats in Europe.

Quinn will not endorse her views but acknowledges a challenge for social democracy. Those, he says, who have enjoyed a liberal education, comfortable lives, and have not seen the displacement of their jobs by technology, may see diversity in a more benign light. Others are less certain.

“Have social democrats failed to recognise the complexity of these issues? Yes.”