“Supporters of independence point out that Catalonia generates about 20% of Spain’s GDP and that Catalonia has succeeded in reducing its budget deficit in recent years to just 0.9% of GDP in 2016. Critics point out that Catalonia’s 35% debt-to-GDP ratio a

one.

Relations between the regional government in Catalonia and the Spanish government in Madrid have been strained for years. Spain has threatened to punish any Catalan official enabling what Madrid sees as an illegal referendum. In a notso-veiled threat, Spain’s army chief said in 2014 that his forces were ready to uphold the Spanish Constitution in Afghanistan or Valencia. Catalonia’s police chief resigned in July, ostensibly because he does not support independence – but Catalonia’s interior minister insisted a week later that Catalonia’s police forces would facilitate the upcoming referendum.

It is unclear exactly what the Catalan government’s objective is. Is the referendum a ploy to try to provoke a Spanish overreaction, thereby increasing support for the Catalan cause? Or does the regional government mean to go through with the referendum, potentially challenging the legitimacy of the Spanish state and creating a hard set of decisions for Madrid on how to respond?

Supporters of Catalan independence point out that Catalonia generates about 20% of Spain’s gross domestic product and that Catalonia has succeeded in reducing its budget deficit in recent years to just 0.9% of GDP in 2016. Critics of Catalan independence point out that Catalonia’s 35% debt-to-GDP ratio and the various impositions Spain and the EU could impose on Catalonia make independence a moot point: Catalonia wouldn’t be able to survive on its own.

And now it appears that the Islamic State has joined the fray, if only to make its enemies experience a little more chaos.

Already, both sides of the Catalan independence issue are exploiting the attacks for political purposes. Independence supporters are suspicious that the central government is using them to crack down on all political activity and thus to prevent a referendum from even taking place. (Madrid has, in fact, beefed up security in Catalonia.) Spanish leaders such as Prime Minister Mariano Rajoy, meanwhile, hope the attack will enable them to brush the Catalonia issue under the rug, appealing to the shared fight against IS as reason to let bygones be bygones.

The secession issue is simple, if not easy. Spain thinks Catalonia is part of the Spanish nation. Catalonia is not sure, and a significant faction of Catalans, invoking the virtues of self-determination, want to decide as much for themselves.

Fair enough, but this is the kind of environment in which the Islamic State’s tactics thrive. Remember that the group rose in Iraq not from strength but from the strife between Sunnis and Shiites. Catalonia and Spain aren’t Sunnis and Shiites, of course, but for the Islamic State, division is an opening, a weak point that it probes for nefarious ends.

The Moroccan nationals who plowed into the civilians in Barcelona and Cambrils set in motion a chain of events that now must be accounted for. Perhaps the Catalan government meant for the referendum to be a ploy to gain concessions for greater autonomy from Madrid, but now that Spain is using the attacks to crack down, the referendum must go forward no matter what.

Or, perhaps, the excuse of an Islamist attack makes the Spanish government act in a way it wouldn’t have without the guise of ensuring security. Whatever the case may be, the situation in Catalonia was already dynamic, and attacks there only introduce more variables that may well shape its outcome.

And yet there are even larger forces at play. Spain does not belong to Europe, at least in the opinion of the Islamic State. Spain is a Muslim land. The Moors ruled this area, known to them as al-Andalus, intermittently from the 8th century to the 15th century, when they were at last driven out entirely. The Islamic State sees Spain as a place to be reclaimed. And it makes sense for the Islamic State to reclaim it, at least from its leaders’ point of view. Islam is the only force in the Arab world that has ever united all its tribes under a single banner. With the Islamic State’s caliphate shrinking, surrounded as it as on all sides by enemies in the Middle East, it needs to inspire its rank and file. Successful attacks, especially in lands it used to control, fit the bill perfectly.

This illustrates the troubled relations between Europe and the Middle East. These two regions have always been connected to each other, and what happens in one affects the other. Instability and violence in the Middle East has led to Muslim migration to Europe. Muslim migration has, in turn, stoked nationalism, sometimes to electoral effect, and has even led to limited European involvement in Muslim wars. This reinforces the belief that Muslim immigrants can’t be accepted by their new countries and wouldn’t want to be even if they could.

In the middle of all this, then as now, is Turkey, a rising power in the region, an area at which Europe and the Middle East meet. Whichever government occupies present-day Istanbul has been able to project power in every direction, and so has been uniquely suited to arbitrate, or suffer under, European and Middle Eastern interests. It was, for example, ground zero in negotiations to house many of the Middle Eastern immigrants whom Europe could not. So far it has largely abstained from the fight against the Islamic State, but a country of its importance, and of its potential, probably can’t stay neutral forever. In the clash of European and Islamic civilisations, Turkey cannot help but be caught in the middle.

This is what makes the attacks in Spain so notable. Terrorism in Western Europe has been steadily increasing since about 2005. Nationalism has been rising in Europe since around the same time. The age-old conflict between Europe and the Middle East, Christendom and Islam, is simmering once more. What happened in Spain last week intersects all three.