Though Spain’s mainstream Socialist party came out ahead in the country’s 28 April elections having won 123 of the 350 seats in the national parliament, the next leftist-led government of Pedro Sánchez will look to govern alone after winning an election that has fundamentally altered the county’s balance of power.

Sánchez will be leading a highly polarised after parliament after his Socialists crushed their mainstream rival, the centre-right Popular Party (PP), but this opened the door for radical parties from both sides of the political spectrum to make significant gains along with Spain’s various separatist parties from Catalonia and the Basque Country.

Sánchez benefitted from campaigning on orthodox left-leaning measures like a 22% rise in the minimum wage and new subsidies for jobless people aged over 52, as well as fighting economic  inequality

The Socialists added 37 seats to their ranks compared to 2016 but fell far short of a majority to form a majority government. Sánchez’ ideological leftist allies, Unidos Podemos, gained 42 seats, giving the incumbent prime minister a combined total of 165 seats, but 11 short of what he needs to remain in office, which will force him to turn to the Catalan, Valencian, or Basque separatist parties for support.

This could galvanise both the centre and the right, both of whom are vehemently opposed to granting substantial influence in the parliament to political parties whose ultimate goal is to break up Spain as a unified country.

The Popular Party’s precipitous collapse was tied to a series of corruption allegations that lost the PPmore than half of its electoral influence compared to the 2016 elections. The PP’s weak showing in the vote has left the moderates on the right in the unenviable position of having to deal with the rise of right-wing nationalist forces for the first time since Spain’s transition to democracy four decades ago.

Vox, which entered parliament by claiming 24 seats, is the first far-right to have a significant following in Spain and have gained seats in the parliament since the death of the country’s Fascist dictator, Francisco Franco, in 1975.

The party was able to appeal to young voters by railing against migrants as well as secessionist forces in Catalonia and the same Euroscepticism that has set in across the EU following years of financial hardship and influx of illegal immigrants from the Middle East and Africa.

In some of its more extreme statements, Vox has called for a “reconquest” of Spain – an allusion to the medieval recapture by Christian forces of the Iberian Peninsula from the Arabs that ended in the late 15th-century.

Sánchez and the Socialists could theoretically avoid an alliance with the far-left and nationalists and take the “Swedish route” to form a government with the liberal-leaning Ciudadanos, which would also split the centre-right.

This has only been floated as a possibility as Ciudadanos leader Albert Rivera ruled out cooperating with Sánchez during his campaign. Rivera is hoping to make further inroads with PP’s electoral base, which would not be likely if he formed an alliance with a traditional leftist like Sánchez. Rivera will most likely continue to highlight his party’s platform, which includes reducing unemployment, improving work conditions, and preventing any moves towards Catalan secession.