-Analysis-

PARIS — It's 11:30 a.m. Tuesday, and French Interior Minister Bernard Cazeneuve addresses the cameras before joining an emergency security meeting called by French President Francois Hollande at the Elysee Palace. At virtually the same moment, Belgian Prime Minister Charles Michel is convening a similar summit in Brussels.

Cazeneuve talks about strengthening French border security, about the need to reinforce European counter-terrorism cooperation, and connect databases for "traditional" crime with those of the Schengen Information System (SIS), which includes information from all the member states of the European area "of freedom and security," including Switzerland.

All the much talked about progress the police have been making since the Nov. 13 attacks in Paris was not enough to prevent a new wave of bloodshed. So how do we explain Europe's deepening vulnerability?

Franco-Belgian police cooperation

We remember the fatal flaw that allowed Salah Abdeslam to leave France, the morning of Nov. 14, in the back seat of a Volkswagen Golf driven by his two accomplices who'd come to whisk him away after the attacks in Paris — Hamza Attoou and Mohamed Amri, both arrested in the aftermath, and still held in Belgium. That morning, in France, the fugitive's vehicle was checked three times between Paris and Brussels, and finally stopped by paramilitary officers near Cambrai. But the officers let the trio go, because the passengers did not show up on the wanted list in France. Some ten minutes later, the name of Abdeslam is reportedly sent by the Belgian police to their French counterparts. But it's already too late.

Since then, things have radically improved. A Franco-Belgian joint investigation team has been established, and French police were also present at the scene of the search in Brussels on Tuesday, March 15, when Abdeslam is believed to have fled by climbing onto the roof. There is also a constant judicial cooperation between the two countries, and the public prosecutor of Paris, Francois Molins, has paid tribute to the European Eurojust judicial cooperation agency at a press conference this weekend, before holding a second press conference in Brussels on Monday with his Belgian counterparts.

Three problems remain however. The first, which applies to all European countries, is the possible existence of "terrorist sleeper cells" sheltered in neighborhoods with a large Muslim population. These cells may have been strenghtened in recent months due to the poorly controlled influx of migrants from the Middle East via Turkey. One suspect — and the most wanted man in Brussels today — Najim Laachraoui, made his way into the country this way. He is said to have been found by Salah Abdeslam in Hungary in the summer of 2015. How many others have followed the same path?

Second problem: the overlap between the worlds of crime and terrorism. The worst-case scenario is when the radicalization of offenders enables the trafficking of false papers, weapons and drugs. Cazeneuve, in fact, has just called for new initiatives against arms traffickers in the EU.

Third and final problem: Despite the unprecedented deployment of police forces, the borders remain porous. Some 5,000 police officers are now assigned to monitor the Franco-Belgian border and manage 220 control points, including 42 permanent ones. But the numbers are misleading. The true closing of borders is today impossible on the continent, and it should also be added, that most acts of terror are committed by national citizens who are locally well established.

What has been done on a European level since Nov. 13 to counter the terrorist threat?

Several extraordinary European summits for interior ministers have taken place. Among the results: the adoption in mid-December of the Passenger Name Record (PNR), a directive to register airline passengers that the European Parliament has blocked hitherto for reasons of privacy protection. It seems, however, according to French Interior Minister Cazeneuve, that updating the Schengen Information System central database is still a problem. Cazeneuve has called for the connection of SIS to the national database of wanted criminals, as well as for the establishment of a European task force against terrorism. This must be immediately accelerated.

It should also be noted, that measures have been adopted by the Finance Ministers to intensify the fight against money laundering and terrorist financing. This system relies on the automatic exchange of information in case of suspicious bank transactions, including small amounts. It also relies on the lowering of the authorized limit of prepaid credit cards, many of which were used to fund the Nov. 13 attacks.

It is however foolish to believe that closer European cooperation will be the short-term solution. These EU policies take time to be adopted and implemented. The most effective measure is direct cooperation between police and intelligence services, as shown by the arrests in Austria and Germany which were enabled through information given by the French and Belgian police. The exchange of information is however complicated as the parties in question are reluctant to share information. It is hard to imagine, for example, that French and Belgian services will now accept to cooperate fully with the Turkish authorities, regardless of the potentially essential information the latter may be able to share.

Should we worry about an uncontrolled influx of migrants?

The identities of several suspects or individuals responsible for the attacks in Paris and Brussels need to be verified. Terrorists, probably sent by ISIS, have made their way in recent months to Europe with the mission to carry out attacks. We know that for months, Greece and Italy, gateways to the Schengen area, were overwhelmed by the mass arrivals of immigrants. From this perspective, the EU's decision in September 2015 to create "hotspots" areas where all arrivals on EU territory must be registered (fingerprints, photographs, etc.) represents a major step forward.

But the reality remains: The routes used by migrants are changing, and many people are already living illegally in countries that are likely to be targeted. Thus, the best response remain the cross-examination of data, and especially the exploitation of traces — telephone contacts, forged documents — left behind by the captured suspects and terrorists who have died in the attacks.

The investigation of the Brussels attacks will tell whether the perpetrators were part of Salah Abdeslam's network, or came from the outside. We must remember two realities: First, the majority of the Nov. 13 killers were of French nationality, and traveling under their own identity; second, the presence of several sibling groups (the Kouachi or the Abdeslam) shows that loose links exist between these groups.

We also see that France's four-month state of emergency, despite its problematic impact on citizen freedoms — more than 400 arrests, 4,000 searches, some 200 legal proceedings instituted for detention of weapons — allowed the police to considerably improve their knowledge of these networks.

Belgian authorities, who had not taken similar measures despite the near-closure of Brussels in mid-November, may again find themselves explaining the choices they have made.