As soon as Friday, the Spanish government could take up arms against its own people. The Spanish parliament is set to approve a call by the central government to suspend Catalonia’s autonomy in response to the region’s successful independence referendum on Oct. 1. The parliament’s vote will kick off Spanish efforts to reassert control over the region—likely by force. Spanish stability may well turn on what happens near the regional parliament building in Barcelona’s Barri Gotic—in the shadow of Roman and medieval relics — as Catalan citizens prepare to form human shields to literally block Spanish direct rule.

This is just the latest unsettling sign that the standoff over Catalan independence could ignite wider violence and even civil war. Observers should not fall into the mistake of underestimating the prospects of civil war — as many were wont to do before the last major civil war on the European continent, over twenty years ago in the former Yugoslavia. In fact, political science research suggests there are more reasons to be pessimistic than optimistic. The political and economic dynamics of the standoff between Spain and Catalonia portend the worst-case scenario of civil war.

Signs of Trouble: State Weakening and Regional Exclusion

One common pathway to civil war involves the weakening or collapse of the state, which can embolden revolutionary challenges to its central authority or create a whirlwind anarchy in which groups compete for security, a dynamic known as a “security dilemma.” At first glance, Spain boasts most aspects of a capable state: it regularly taxes its citizens, provides security, and facilitates economic investments, in contrast to countries from Somalia to Iraq, whose failed or sporadic governance has facilitated widespread violence.

But the strength of the state’s authority in Catalonia was called into question this week when regional and local Catalan police were accused of defying national court mandates to disrupt the vote, and in some cases even clashing with the national police that was deployed to the region on voting day. (Catalonia could staff a formidable resistance movement by coopting ready-made institutions like the autonomous regional government’s police force, the Mossos d’Esquadra, as well as the municipal policemen or the now-iconic firefighters.) This episode of Catalan police insubordination, as well as subsequent instances of regional leaders resisting the Spanish government’s orders, illustrate the very pathway to civil war through a weakening of the state’s administrative capacity that numerous scholars have catalogued.

A similar erosion of central power occurred in Yugoslavia. Indeed, Spain’s approach of allowing self-government for its four most restive nationalities strongly resembles the Yugoslav model of an umbrella government over numerous regional republics.

One of the most robust findings in the literature on civil wars is that they tend to occur in areas where economic development, as measured by per-capita gross domestic product (GDP), is low and economic growth is slow. On these points, Spain’s record is mixed. Its $25-30,000 per-capita GDP since 2010 is well above the threshold at which the probability of civil-war drops to below 10%, but Spain is still grappling with a “great recession” and growing debt since the 2008 global financial crisis. The most interesting application of the literature to the Spanish case has less to do with simple economic indicators, and more with the reason that poorer countries are associated with civil wars. Convincing empirical work has shown that ethnic conflicts are more likely to happen where economic exclusion of an ethnic group is high, a factor that actually changes the effect of per-capita GDP on the probability that civil war will break out. Unfortunately, this is another indicator for civil war that Catalonia meets.

Catalonia is Spain’s most prosperous region, but it has arguably lost the most from the central government’s economic policy. Against the backdrop of national financial crisis, Spain’s redistribution policies have disproportionately affected Catalonia. The central government controls tax collection and determines the piece of the pie that the Catalan regional government is given to spend. Moreover, Catalonia’s share of federal funds is shrinking in proportion to the region’s actual tax contribution, given rising redistribution during the economic crisis. Catalan pro-independence activists especially resent that they cannot control how their own tax revenue is used. The comparison to Yugoslavia on this point is also uncanny: Slovenia and Croatia were well-off republics that resented sharing their prosperity with the rest of the country. They leveraged this grievance, paired with their relative economic advantage, to hold independence referenda and secede in quick succession in 1991, inspiring Bosnia to follow suit and igniting the fire that would become the Yugoslav wars.

The same scholarship that found that economic exclusion predicts violence found that political exclusion does, too. There remains disagreement about whether this applies to Catalonia. Critics of Catalan secession argue that Catalonia has no basis upon which to claim political exclusion, given that it is basically self-governing, complete with its own parliament, presidency, regional police force, and education and health systems. However, the recent empowerment of Catalan pro-independence parties shows how this very decentralization can actually encourage ethnic conflict: decentralized states are more prone to developing regional parties or “ethnic entrepreneurs” who can benefit by stoking ethnic identities for political gain and mobilizing their populations toward secessionism or wider violence.

More importantly, however, these critics gloss over the historical foundations of Catalonia’s grievances, which have been revived in recent years. Just before the Spanish Civil War, Catalonia had established a strong self-governing republic and in 1934 briefly declared independence. Its hopes of autonomy were dashed when the Spanish army occupied the region and arrested its pro-independence heroes. Furthermore, countless Spaniards still remember the callous tactics of dictator Francisco Franco—especially in Catalonia, where ethnolinguistic expression was banned.

A key event in 2010 reignited sentiments of political exclusion. In 2006, Catalonia, and later the Spanish parliament, ratified a new regional constitution that expanded the regional government’s authority. Several legal challenges to this Statute of Autonomy reached Spain’s highest court, which controversially rescinded a number of provisions, inciting mass protests across Catalonia. The court annulled preferential treatment of Catalan language in educational instruction and other administrative contexts and clarified that the use of “nation” to describe Catalonia in the preamble carried no legal weight, among other decisions limiting Catalan autonomy. The verdict revived a feeling of ethnolinguistic exclusion that fueled an increase in pro-independence popular opinion and the rise to power of Catalan pro-independence parties.

In perhaps the most alarming parallel to Yugoslavia, a number of nations within Spain have separatist aspirations, and an independent Catalonia could be just the first of many dominos to fall. Basque Country, for instance, has similar grievances as Catalonia. It followed Catalonia’s example of codifying self-government in the 1930s, and similarly found its aspirations spoiled by war and its citizens’ self-expression suppressed under Franco. More recently, the decades-old Basque nationalist terrorist group the ETA made the threat of violence a constant presence in Basque Country until a ceasefire in 2010.

This is all to say that regionalist and ethnonationalist movements across the country are looking to developments in Catalonia with great interest and will seek to learn from its experiment in self-determination. Indeed, many Basque leaders have criticized the Spanish government’s approach to the standoff, saying that its suspension of Catalan autonomy was a dangerous precedent that could lead other regions to “turn their backs” on the central government. In many places, the tensions between regionalists or ethnonationalists and supporters of the Spanish government are already at risk of boiling over, as exemplified by street clashes a few weeks ago between groups advocating for independence for the Valencian region and their naysayers.

It would be difficult for the Spanish state to accept Catalonia’s secession without considering the possibility of further secessions. Catalan independence could therefore reveal the fragility of the project of Spanish governance, which is why the state may be willing to go to war to preserve it.

What Can We Do Now?

Political science not only helps us predict conflict; it also offers insight on how to avoid it.

The Catalan regional government has indicated that it prefers negotiations, giving Spain several opportunities to pump the brakes on the looming conflict. The Spanish government could negotiate some appeasement of Catalonia’s economic grievance over redistribution (the major accelerant of the current independence push). Even many within Basque Country claim that separatist sentiment there has decreased in large part because Spain has successfully assuaged their economic resentment. The central government could also make amends for the recent forceful tactics and reverse the recent exclusionary legal verdicts that have fueled Catalans’ political grievances.

Spain could also forestall violence by avoiding actions that might enhance the security dilemma. Continued repression or heavy-handed governance would only increase Catalans’ perception that they need to defend themselves, which would in turn inspire Spain to do the same, creating a spiral of confrontation that is often hard to reverse. To draw another comparison to the former Yugoslavia, in 1981 thousands of Kosovar Albanians gathered to call for more autonomy, but were met by a Serb crackdown, a revocation of whatever autonomy they had had up to that point, and years of repression; this set the stage for the Kosovo rebellion and later civil war. .

The Spanish government’s riskiest option, however, would be to curb Catalan self-protection forces, such as forcibly disarming or arresting the police or firefighters who were seen as the defenders of Catalan self-determination. Unfortunately, this is not outside the realm of possibility, as Spain is already investigating the local police for insubordination. A string of arrests of other Catalan leaders had already mobilized people to protest in the weeks preceding the referendum; similar actions now will likely continue to fuel the fire of independence—and justify more robust resistance. In the years before the Yugoslav wars, the central government reduced the weapons caches from locally based Territorial Defense Forces, increasing these republics’ incentives to preemptively act before their main tools for defense were eliminated.

For its part, any actions by the Catalan regional government to increase the strength or widen the mission of its local police forces would aggravate Spanish fears of a violent challenge to the state, especially given the longstanding fear over violent Basque terrorism. Catalonia’s regional president has already invoked the language of the security dilemma, describing the latest Spanish move to reassert control over the region as an “attack” that cannot be accepted. The response by Catalan regional forces will be critical in determining whether Catalonia turns to an organized rebellion or disorganized civil unrest.

The aforementioned “ethnic entrepreneurs” also have a role to play to prevent violence. A mostly linguistic-identity-based appeal for independence has so far failed to unify all populations within Catalonia behind independence—in polls before the referendum, 49% of Catalans actually opposed independence, consistent with only a 43% turnout on voting day. A continued reliance on this identity-focused message could drive minorities and non-Catalans to support the Spanish government using whatever means they have—violent or otherwise. Instead, Catalan leaders should consciously assure these people that they would also be included in an independent Catalonia, lest they face challenges from within, just as Croatian nationalism created an opportunity for Serbia to mobilize an internal minority, the Croatian Serbs, against Croatia in the early 1990s.

This piece is written in the explicit hope that it is wrong—that Spain is not edging along the path to war, that cooler heads will prevail, and that peace and diplomacy carry the day, as was the case with a major success story about steering secessionist sentiment away from war. In 2014, the United Kingdom held a referendum on Scottish independence that failed to pass, but instead of ignoring the grievances that led Scots to the polls, the government followed up the referendum with legislation to enhance Scottish autonomy. If it turns out that past is prologue, policymakers can at least use the lessons of political science to minimize the risk of serious conflict over Catalonia.

Sara Plana is a PhD student in the Department of Political Science at MIT, where her research focuses on structures of armed groups, civil-military relations, and civil war. Prior to MIT, Sara worked as a country analyst for the Department of Defense in Washington, DC. Follow her on Twitter @saracplana.

Image: Flickr/Claudia Schillinger