Spain will vote on Sunday to try to break the country’s political deadlock, but the rise of a far-right party and the still-unanswered question of Catalonia are making it an unpredictable election.

Spain’s politics are extremely divided. Two political parties traditionally dominated the landscape: the center-right Partido Popular, better known as the PP, and the center-left Socialist Worker’s Party (Partido Socialista Obrero Español in Spanish), or PSOE (whose leader, Pedro Sánchez, is the current prime minister).

But, in recent years, a number of smaller parties across the political spectrum have eroded their power and support.

The fractures in Spanish politics are a symptom of larger issues in the country, including a still-struggling Spanish economy and the status of Catalonia, an autonomous region that held an independence referendum in 2017 and has fueled a new wave of Spanish nationalism and increased support for far-right parties like Vox.

All of this is making the outcome of Sunday’s elections very uncertain. The center-left PSOE, the current ruling party, is leading the polls and is expected to gain seats in Spain’s Congress.

But PSOE is unlikely to win an outright majority — meaning it will have to join with other parties to form a government, or at least make an attempt. Experts told me it’s possible that the party could fail to do that, which would force yet another election. Or, a more surprising scenario could play out, including one where right-wing parties win a majority of seats.

Sunday’s elections will take place against this fraught backdrop. Some of this political chaos, including the rise of the far-right in Spain, mirror larger trends across Europe. But there are also marked differences in Spain’s experience compared to other countries on the continent.

Here are five important things to keep in mind before voters head to the polls.

1) These are snap elections. The prime minister called them to try to break the political gridlock.

In June 2018, Spain’s former Prime Minister Mariano Rajoy was ousted in a no-confidence vote after his party, the center-right PP, became embroiled in a truly massive corruption scandal. This paved the way for Sánchez, of the PSOE, to become the current prime minister.

But Sánchez had to rely on a lot of smaller parties to oust Rajoy, including those representing the Basque country and Catalonia, two autonomous regions in Spain that have strong independence movements.

Sánchez’s coalition was extremely fragile to begin with, and it eventually crumbled when the Catalan parties and one Basque party rejected Sánchez’s budget, along with the opposition, in February 2019.

The prime minister called snap elections for April as the only way to possibly shore up power (the PSOE only had 84 seats in its 350-member legislature, called the Congress of Deputies) and break the impasse.

But it’s not exactly clear that these elections will end this deadlock.

2) Spain’s politics is extremely fragmented

Spain’s political system has always included smaller parties, but two main parties usually dominated — the PP on the right, and the PSOE on the left.

But the political landscape began fragmenting more dramatically in the wake of the 2008 economic crisis and unsteady recovery, and, more recently, the Catalonia independence referendum in 2017.

Many Spaniards were frustrated by the establishment’s response to the financial crisis, which included an austerity program. It bred disillusionment and distrust, especially with PSOE, which held power during the 2008 meltdown, and later with the PP, which won elections in 2011.

“At least for the left, it completely put on the table this idea that the establishment was old, the establishment was not willing to change — especially the leftist establishment, which was embodied in the PSOE,” Bécquer Seguín, a professor of Iberian studies at Johns Hopkins University, told me.

This climate gave rise to Podemos, a left-wing party that grew out of the 15-M protests in 2011 against the government’s handling of the economic crisis. (Think Spain’s version of an Occupy Wall Street movement.)

Podemos’s once challenged PSOE for dominance, but its rise has since stalled. But it’s still an electoral force — and it’s not the only party that’s upended the two-party stronghold.

The center-right Ciudadanos, founded in 2006, also emerged around this tense period. The party was seen as an outlet for those fed up with the PP. It was also established as an antidote to Catalonian nationalism, since it strongly opposed the idea of Catalan secession.

Ciudadanos is struggling to define exactly what its centrist message is amid a rise of the far-right in Spain — specifically, Vox, and its explicit embrace of Spanish nationalism driven, in part, by the fallout from Catalonia’s failed independence bid in 2017.

None of these secondary parties — Podemos, Ciudadanos, or Vox — are expected to win on Sunday. But each is expected to secure a share of seats in Spain’s Congress.

3) Catalonia’s failed independence bid is haunting this election

Catalonia, which has Barcelona as its capital, is one of the most prosperous of Spain’s 17 autonomous regions. It speaks its own language, Catalan, has its own cultural traditions, and has long nurtured a restive independence movement. That movement intensified in recent years for a few reasons, including a sense that Catalonia pays a lot in taxes to Madrid, but that goes to the rest of Spain, rather than back to Catalonia.

So in 2017, the Catalan government called for an independence referendum, and even though turnout was low, voters opted to secede from Spain.

The courts, however, deemed the referendum illegal, and the Spanish government tried to stop the referendum and engaged in a violent crackdown to prevent people from voting.

The Spanish government then responded Catalonia’s independence declaration by imposing direct rule on Catalonia and dissolving its regional government. Madrid lifted direct rule in June after a new Catalan government came to power, but separatist remain in control of the region.

The Catalan question remains an open wound in Spanish politics, one that’s particularly acute during these elections because 12 separatist Catalonian leaders are currently on trial for rebellion, a televised affair that’s captivating the country.

But Catalonia’s breakaway attempt also has deeper implications for Spanish politics, and it helped instigate a resurgence in Spanish nationalism on the right.

Spain has 17 autonomous communities with distinct regional identities, but Spanish nationalists support a central Spanish identity as trumping those regional loyalties. The ideology has its echoes with the dictatorship of Francisco Franco, who ruled Spain for 40 years, and sought to impose one Spanish identity on the country, and crush dissent in places such as Catalonia and the Basque country.

This Spanish nationalism is a direct response to the regional nationalism in Catalonia. Catalonia’s grievance that its wealth was being unfairly redistributed to the rest of Spain didn’t generate sympathy among some Spaniards — it offended them. As the Los Angeles Times put it in November 2017, “the push for Catalan independence is a stinging rebuke of all Spaniards, particularly those who reside in less well-off regions.”

The PSOE doesn’t support Catalonian independence, but Sánchez has been willing to negotiate and reach concessions with Catalan secessionists. This has fueled a backlash on the right among parties like the PP and Ciudadanos, who strongly oppose Catalan secession and see outreach as “treasonous.”

And those more mainline right-wing parties are under pressure from Vox, the extreme Spanish nationalist party that’s rattling politics and this upcoming election.

4) Spain’s new far-right party called Vox is gaining strength

This xenophobic, nationalist party has been slow to catch on in Spain and was formerly thought to be an outlier. But that may be about to change.

Vox is likely to gain at some seats in Spain’s Congress for the first time, a stunning development for a country that hasn’t had a real far-right movement since dictator Francisco Franco’s regime ended with his death in 1975.

The Vox party was officially launched in January 2014. Breakaway members of the center-right PP formed the party, disgruntled by what they viewed as the PP’s lackluster economic policies and weak response to separatists in Catalonia and the Basque country.

Vox shares similarities with other far-right movements in Europe, such as the National Front in France or Alternatives for Deutschland (AfD) in Germany. Vox is anti-immigrant, anti-Muslim, and skeptical of elements of the EU. It is also very conservative on issues like LGBT rights, abortion, and women’s rights.

A right-wing firebrand named Santiago Abascal founded and currently leads Vox. Abascal is a 43-year-old former PP member and a gun-toting politician. He’s also been endorsed by Steve Bannon.

Abascal’s rhetoric focuses on Spanish identity — “los españoles primero,” a version of Spain first — and he has defended what he sees as cultural traditions under siege, like bullfighting. Vox rallies brim with Spanish flags.

Vox’s platform emphasizes the idea of a more centralized Spanish state over the current system of 17 autonomous regions. It’s a plan that would alter the constitutional structure that’s been in place since Spain became a democracy in 1978.

Vox wants to “conserve and preserve the Spanish state,” Gema Sánchez Medero, a professor at Universidad Complutense de Madrid, told me.

There’s a strong anti-immigrant component to Vox, too — though experts told me that this is part of why Vox’s rise is so complicated, and surprising, in Spain. At first, no one really took Vox all that seriously, and the xenophobic rhetoric failed to gain traction in Spain as it did elsewhere in Europe.

Many observers thought Vox’s message turned off Spaniards precisely because of the fact that it reminded them of Franco and his 40-year dictatorship, which kept Spain fairly isolated until after his death, and until Spain joined the EU in the mid-1980s. That’s not all that long ago for many Spaniards.

Spain has also been fairly receptive to migrants and refugees, though it also didn’t deal with the influx of refugees that arrived to other parts of Europe at the height of the crisis in 2014 and 2015.

That doesn’t mean tensions don’t exist. Spain did see a surge in migrants in 2018, when it became the primary arrival point for people coming by sea to Europe from places in Africa and the Middle East. (Though overall migration to Europe fell.) That, combined with still-high unemployment in the country and the issue of Catalonia, may have made Vox’s anti-immigrant message much more appealing.

“So where you see these tensions flaming up is really along certain coastal cities and certain coastal towns that have a vastly disproportionate amounts of immigration,” Seguín, the Johns Hopkins professor, said.

Vox’s big break came in December 2018, when it won 12 seats in the regional government of Andalucía, in southern Spain — one of those coastal regions that saw more migration. Vox formed a government with other right-wing parties, the PP and Ciudadanos. This victory for Vox in Andalucía, as the Guardian put it, “ended four decades of Spanish exceptionalism and showed that the country’s fabled immunity to far-right politics had finally given out.”

Experts stressed to me that the national reach of Vox won’t really be clear until after the elections on Sunday. The party is polling at about a little more than 10 percent in the current elections — which could give it about 30 seats in Spain’s Congress. That would be a significant share, and far more than the less than 1 percent the party won in 2016 elections.

“People don’t worry about them having a majority of seats — that would be very, very shocking,” Laia Balcells Ventura, a professor of government at Georgetown University, told me. “But [there is a] possibility of a coalition between the three right-wing parties: PP, Cuidadanos, and Vox.”

Vox’s biggest threat might be that their extremist message is pushing the other parties such as PP and Ciudadanos further to the right as they try to compete for voters. Again, the Catalan crisis is still the driver here, and all three right-wing parties are competing to show how tough they can be on Catalan separatists. Or as Balcells put it, they’re trying to prove who can be “the most Spanish nationalist of them all.”

5) The ruling PSOE will likely win the most seats — but after that, who knows

The most recent polls suggest that the center-left PSOE has more than 30 percent of the vote, putting them on track to win a little more than 135 seats in Spain’s Congress, but falling well short of what they would need for a majority.

If that happens, then the PSOE will need to form a government with other parties. The question is, with who? The obvious choice is with Podemos (which is an alliance composed of other left-wing parties), but it’s not clear that Podemos alone will win enough seats to make up a majority.

This means it’s possible PSOE will need to join forces with some of the smaller parties in the Spanish legislature, which would probably include regional parties that represent Catalan and Basque county. And that would basically leave Sánchez, the PSOE leader and current prime minister, back where he was before he called snap elections.

Smaller regional parties can use their outsize influence to hold up legislation, as they did in budget negotiations in February. Why would they do this? Well, it all goes back to the Catalan crisis. Halting other matters can be used as leverage for concessions on the independence question, the most politically charged issue in Spain.

A government coalition led by the PSOE seems the most likely. But a huge chunk of voters — about a quarter — remain undecided, so that’s a lot of uncertainty in the electoral outcome. It also still leaves open the possibility that right-wing parties could win a majority, allowing the PP, Cuidadanos, and Vox to form a government together.

Whatever government emerges may be marriages of convenience and not all that beneficial to stable governance — meaning Spain’s political impasse would start anew. Then again, if Sunday’s the vote is extremely divided, Spain may find itself unable to form a government at all.

Update: This post has been updated to note the courts declared the Catalonian referendum illegal before the vote, and to correct a quote from Seguín.