The recent events in Paris have once again cast doubts on the ability of French intelligence to provide national security.

Following the attacks, French Prime Minister Manuel Valls did not hesitate to admit to a lapse in security. The two Kouachi brothers, responsible for killing 12 people, were well known to French intelligence agents and for a time closely tracked. Yet they managed to slip through.

This is particularly troubling since the French domestic intelligence services (DGSI) were reformed in 2008 and again in 2014 following the attacks carried by Mohamed Merah, a French citizen who gunned down several French soldiers and Jewish schoolchildren in three separate incidents.

The apparent recurrence of intelligence failures in France and elsewhere has long been debated by security experts, and ultimately begs the question: what can be expected from intelligence services?

What’s reasonable?

French journalists recently pointed out in Le Monde that citizens expect 100% security. Yet intelligence services make very clear that such levels of security are not materially possible.

The British Secret Intelligence Service states on its website: “we are likely to see a more unpredictable picture in the future, potentially with more frequent, albeit less sophisticated attacks.” Similarly intelligence scholars have long agreed that “intelligence failures are inevitable.” In other words, citizens should not expect too much from their intelligence services.

Jacky Naegelan/Reuters

A difficult, if not impossible task

In continental Europe, the task of domestic security services, expected to monitor potentially dangerous individuals and provide national security, has been significantly complicated by the growth of “Jihadi tourism.”

More than a thousand aspirant-terrorists have traveled from Europe to Syria in recent years.

The risks posed by these individuals when they return home have been very clearly demonstrated by Mohamed Merah’s attacks in Toulouse and Montauban, Mehdi Nemnouche’s attack at the Jewish museum in Brussels, and more recently by at least one of the Kouachi brothers who received training in Yemen before staging the attack on Charlie Hedbo.

Government authorities have passed laws allowing the confiscation of would-be jihadists’ passports but this may not be enough.

So many potential “threats”

Would-be jihadists are now present all-across Europe and this has put immense pressure on security agencies, which are expected to monitor and counter this growing threat.

In such circumstances, electronic surveillance proves useful but it is limited. French intelligence stopped eavesdropping on the Kouachi brothers in June 2014 because their conversations did not appear to refer to any major security risk.

When the terrorist intent is clear enough, intelligence services employ both electronic and physical surveillance. The latter type of surveillance is notoriously time consuming, expensive, and places high demands on domestic security services.

According to security expert Roy Godson, clandestine surveillance around the clock “requires at least twenty-four people and twelve cars.” Multiply this by the number of individuals judged to be at risk in France and elsewhere in Europe and the necessary resources quickly become colossal.

In such situations, it should not come as a surprise that the French DGSI is said to lack capabilities.

Room for improvement

But all is not lost.

Despite these difficult conditions, French intelligence did manage to thwart at least a handful of major plots in the last couple of years.

And the Belgian police recently rounded up a group described as Jihadi militants, “on the verge of carrying out attacks.” Commentators have discussed a host of improvements, some of which are already being implemented by governments.

Experts have called for greater pan-European security cooperation to share resources and costs, and to compensate for the lack of border security checks that results from the free movement of goods and people among countries that have signed the Schengen agreement.

This approach could be broadened and applied to transatlantic cooperation, which could, for example, lead to even more intelligence sharing between the US intelligence community and multiple European partners.

The French government has committed to invest more resources in its intelligence and security services. Some experts have suggested that the French laws regulating surveillance should be amended to give more flexibility to the services. Others argue that the analytical capabilities of the French intelligence apparatus need to be improved to better connect the dots.

Living with uncertainty

However, augmenting and improving intelligence capabilities can only do so much. Even when the dots are connected, there remains the challenge of persuading decision-makers to act.

More generally, security capabilities cannot be increased indefinitely. Critics will condemn the growth of an almighty “security state.”

Given the myriad of challenges faced by intelligence professionals, common wisdom in the field of security points out that intelligence is ultimately a human endeavor and as such it is inherently imperfect.

The resulting conclusion is a sobering invitation to revise our expectations and accept relative levels of insecurity while striving to improve the use of intelligence to counter terror.