In the wake of any shocking event, national governments and officials of the European Union invariably call for more cooperation between member states to prevent anything similar happening in the future. The response to the March 22 terrorist attacks in Brussels has been no different.

Following the attacks, the governments of Germany, Italy, France and members of the European Commission demanded a global response to the terrorist threat. The commission's president, Jean-Claude Juncker, even proposed the creation of a "security union" to combat terrorism at the continental level. In a March 24 meeting, ministers at the EU Justice and Home Affairs Council highlighted the need to share information among member states to fight terrorism. But despite the calls for greater cooperation among EU members, the national interests of individual member states will prevail in the long run, limiting the possibility of integration within the bloc on security issues.

As it stands, the European Union already has several continent-wide security structures in place. The European Police Office (Europol) handles criminal intelligence and combats international organized crime, while Frontex manages cooperation between the national border guards that secure the European Union's external borders. Eurojust, in turn, coordinates investigations and prosecutions among EU members, especially for transnational crimes. Because their duties are mainly logistical, coordinating efforts and resources among states, these agencies have little staff and equipment of their own.

The European Union faces obstacles to establishing a unified security network. For one thing, the organization's 28 member states have different priorities, resources, and levels of expertise when it comes to fighting international crime and terrorism. Large countries such as France, the United Kingdom and Germany have significant counterterrorism experience and enough human and material resources to maintain sophisticated intelligence and anti-terrorism agencies. This is not true of smaller countries with less expertise and smaller budgets — and even less so during economic crises, when smaller governments must weigh financing their security apparatus against controlling fiscal deficits.