“Italy is the leader,” said Steve Bannon in an interview just before the Italian elections. “The Italian people have gone farther, in a shorter period of time, than the British did for Brexit and the Americans did for Trump.”

Bannon delights at the realisation that in Italy the centre no longer holds. Indeed, these elections have certified the collapse of established parties and left the country’s political mainstream in chaos. Taken together, the incumbent Democratic party of Matteo Renzi and Silvio Berlusconi’s Forza Italia have gathered a puny 33% of the popular vote between them. For comparison, at the last elections the Democrats alone scored 40%. Any grand coalition is arithmetically off the table in Italy.

The parallel declines of Renzi and Berlusconi is telling of a more general trend: the growing disenchantment with parties appearing to uphold continuity. Leaving corruption and clownery aside, the political platform of the traditional centre-left and centre-right is a similar promise of business as usual and adherence to the precepts of neoliberal economics. It is no coincidence that the EU establishment recently hailed Berlusconi as the man to save Italy from populism. While, in a trend consolidated across the west, social democracy becomes associated with elite interests and is abandoned by the working class.

Will a new anti-establishment, leftwing alternative rise up to fill the vacuum? Some appear to be thinking this

It comes as little surprise that the true winners of these elections are two parties perceived to be campaigning to upturn the system. Matteo Salvini’s nationalist and xenophobic La Lega (“the League”, formerly known as the Northern League) has surpassed Forza Italia to lead the rightwing camp with more than 17% of the vote. But the real winner of the elections is the anti-establishment Five Star Movement, led by Luigi Di Maio, which reached a whopping 32% and enshrined its position as Italy’s largest party by far. The two upstarts seem to have divided the country between themselves: the League is by far the most influential political force in the north, while the Five Star Movement has won virtually every constituency in the south.

This is to be expected. Extraordinary wealth concentration, a grossly unfair taxation system and a stagnating economy that produces precarious and underpaid employment even in times of growth are enduring characteristics of Italy’s – and Europe’s – economic landscape. It is far from incomprehensible that many would wish to overturn it.

‘Part of an international trend of growing nationalist and xenophobic movements.’ Matteo Salvini of the League. Photograph: Riccardo Giordano Sicki/IPA/Rex/Shutterstock

As is the case for Renzi and Berlusconi, Salvini’s and Di Maio’s stories also run in parallel. Both have flirted with the idea of Italy exiting the euro, only to tone down their message as the elections approached. Both try to appeal to left-behinds, including many of Italy’s small and medium enterprises, shaken by years of economic crisis. And both mix an apparently anti-elite rhetoric with policies of continuity. The League advocates a flat tax, a measure benefitting by and large the richest households, while the Five Star Movement has repositioned itself as a guarantor of economic stability, advancing moderates as candidates for ministerial posts. What guarantees the anti-establishment tone of both parties is scapegoating: migrants for Salvini, corrupt politicians – the “caste” – for Di Maio.

But while the League is part and parcel of an international trend of growing nationalist and xenophobic movements, Five Star is a peculiarly Italian phenomenon. It has drained votes from the centre-left and it has gradually toned down its rhetoric to occupy an increasingly moderate position. It is an extraordinary example of new centrist populism.

What government may come out of this situation is anybody’s guess. Both Salvini and Di Maio have claimed the right to try to form a majority, but for both the path is arduous at best, with no obvious coalitions available in the newly elected parliament. A “populist” government bringing the two anti-establishment forces together – a nightmare scenario for the EU – is certainly a possibility, although Di Maio hesitates to identify his catch-all party too closely with the far right. Coalition talks are likely to be lengthy, during which time the incumbent prime minister, Paolo Gentiloni, will follow Mariano Rajoy’s and Angela Merkel’s ordeal of governing without a majority. Early or repeat elections are a distinct possibility.

But while all eyes will be focused on coalition talks, the most interesting developments may yet appear on the left. The leftwing vote at these elections has amounted to little more than 22%. The scope for disruption, in a country where at least double that number has traditionally voted left-of-centre, is huge. Calls for the resignation of Renzi multiply. Will the Democratic party manage to react to the burning defeat by reinventing itself, following Jeremy Corbyn’s example with the British Labour party? Or will it, on the other hand, attempt to copy Emmanuel Macron’s En Marche and re-brand itself as a pro-European, liberal party?

And, while the Five Star Movement moves towards the centre, will a new anti-establishment, leftwing alternative rise up to fill the vacuum? Some appear already to be thinking in this direction. On 10 March, less than a week after the elections, the charismatic mayor of Naples, Luigi de Magistris, and the former Greek finance minister, Yanis Varoufakis, are due to meet in Naples, together with a large cohort of European progressives, to launch a new pan-European political party. It would be surprising if they had no ambitions to occupy a space left empty by the collapse of the Italian left.

Ultimately, the only certainty is that Italy’s political landscape – just like Europe’s – is in a complete state of flux. The collapse of traditional parties is welcome and long overdue. But it remains to be seen whether this will lead to the kind of right-wing backlash that Bannon so revels in, or whether it will open the opportunity for a genuine progressive transformation. The Italian elections have shaken the tree. But the fruits still have to ripen.

• Lorenzo Marsili is a writer and philosopher, and the founder of European Alternatives