‘I am not afraid’, chanted the crowd that took to the streets in Barcelona after a van was driven into pedestrians on the Las Ramblas promenade, killing at least 14 people and injuring some 130 others. It was the most dignified and appropriate possible response to a terrorist attack, a firm demonstration of unity that transcended internal divisions. While rifts between, say, Spaniards and Catalonians will surely re-emerge soon, that fundamental sense of unity must endure.

Following attacks in Paris, Brussels, London, Nice, and Berlin—not to mention Madrid in 2004—the choice of Barcelona as a target should come as no surprise. Barcelona is not just the European city that has attracted the largest number of immigrants from the Maghreb, especially Morocco; it is also a symbol of intercultural dialogue and tolerance.

In fact, Las Ramblas—one of the city’s most popular tourist attractions—is itself a symbol of openness: more than 30 nationalities were represented among the victims. One of the suspects subsequently confessed that his terror cell was also planning to use explosives against major monuments, including Barcelona’s world-famous Sagrada Familia church—a clear sign that they were attempting to strike at the soul of the city.

Such symbolic attacks are particularly important today. With the Islamic State (ISIS), the main inspiration for transnational terror nowadays, facing near-total defeat on the ground, the group is scrambling to use what weapons it still possesses—namely, its ability to inspire young would-be terrorists around the world.

International ISIS ‘sleeper cells’ do not necessarily comprise graduates from ISIS training camps in countries like Iraq and Syria, as was typically the case with al-Qaeda attacks in the past. Rather, they are composed of second- or third-generation immigrants from Muslim countries who feel disconnected from both their home country and that of their grandparents. They are eager for a sense of purpose and identity—emotional goods that radical Islam, and ISIS ideology in particular, can offer.

In the case of the Barcelona attack, the Moroccan imam Abdelbaki Es Satty, who died in an explosion at the terror cell’s bomb-making factory, is thought to have been responsible for radicalising the young attackers. But such a clear conduit is not always needed; the perpetrator of the Manchester Arena bombing in May had associates who knew of his plans, but he was not part of a terrorist network.

Although ISIS’s self-styled caliphate is on the brink of collapse, an increase in terrorist attacks abroad is possible. This may encourage more Muslims in Europe to denounce loudly such actions, as the ‘not in my name’ movement has done. It will certainly drive governments to pursue more prosaic measures.

France, for example, has already announced plans to re-establish the so-called ‘proximity police’, in charge of community-level surveillance. Such policing can be a tool of both information and deterrence, and can thus serve as an effective component of a broader strategy, including measures ranging from beefing up border police and intelligence services to military intervention in the Middle East or Africa.

But none of this will suffice to address the identity crisis of the second- and third-generation immigrants who have proved vulnerable to ISIS ideology. The most effective way to tackle that problem is to advance integration, through concrete policies that support education and social assimilation, as well as more open dialogue among various groups.

The problem, of course, is that such a strategy takes time to show results, and time is something that Western democracies lack when it comes to terrorism. Beyond the direct danger of further casualties, there is the growing fear among populations, which populist politicians are eagerly attempting to exploit.

So far, Western democracies have largely resisted the siren song of xenophobia, and remained broadly faithful to liberal values. If ISIS wants to plant seeds of division and chaos in the West—especially Europe, which ISIS considered to be the weak link—it has so far failed.

But the war against Islamist terrorism is far from over. We must remain patient, resilient, and united, within our communities and countries—and also as Europeans. The recent knife attack in Finland, carried out by a Moroccan teen, underscores the reality that a country need not play a major role in the coalition against ISIS in Syria and Iraq to become a target; it is enough to be an open European society.

Given this, it is not enough to say, ‘We are all from Barcelona’. We must, instead, say, ‘We are all Europeans’. That is not just a symbolic statement; it is a descriptive one, which should be guiding our response to the terrorist threat. While national-level action, such as Spain’s anti-terror cooperation with Morocco, is necessary, it can work only in the context of broader European action, including intelligence-sharing, migrant policy, and collaboration among police and security forces.

Today, as the United States’ role as a stable actor and a legitimate model erodes, Europe must do more to fill its shoes. Islamist terrorism can either undermine or strengthen this effort. A decisive victory in the fight against Islamist terrorism is possible only if that fight serves as a source of unity in Europe, one that reinforces our deep-rooted connections and our shared democratic ideals.