When Salah Abdeslam, the prime surviving suspect for November's Paris attacks, was captured by Belgian police after a shoot-out on Friday, one French minister hailed the arrest as a body blow to Islamic State.
Belgium's interior minister, Jan Jambon, was more cautious. He said the country was on high alert for a revenge attack and warned: "We know that stopping one cell can . . . push others into action." On Tuesday prime minister Charles Michel admitted as much: "What we had feared has come to pass. Our country has been struck by attacks that are blind, violent and cowardly."
The attacks, taking at least 34 lives, underlined in a particularly brutal way the vulnerability of an open society, no matter how well prepared. Buildings can be protected, but it is almost impossible to seal off or secure transport hubs from attack without paralysing societies. The lockdown of the city’s transport in the aftermath of the attacks illustrates the reality all too clearly.
Inevitably questions will be asked about whether the Belgian authorities could have done more to anticipate the attacks, to penetrate the cells where the attacks were hatched, to disrupt the flows of weapons.
Clearly there remains a failure to understand the alienation that drives young people into the arms of Islamic State – Belgium has seen more of its young per capita head to Syria than any other EU state. And it was possible for Abdeslam to remain hidden for months in the safety of his old community of Molenbeek, able to network with those who planned their revenge.
There are also questions about whether intelligence-sharing among EU states and even between competing security agencies in some states is all that it should be.
Some of such criticism amounts to a counsel of perfection – because there has been a failure of intelligence does not mean, ipso facto, someone has failed. And there are also, rightly, limits set to what police and intelligence agencies can or should be expected to do in a free society. The availability of the technical means enormously to expand intelligence capabilities, notably surveillance, does not mean they should be used.
The knee-jerk response of Eurosceptics in more than one country should also not be countenanced. A Ukip spokesman on Tuesday cynically enlisted the attacks to the cause of Brexit by insisting they proved that the EU’s “open borders are putting lives at risk”.
Yet, from what we know of Abdeslam and his Molenbeek circle, we are dealing with a home-grown terrorism phenomenon – “open borders” are not the problem. The attacks do, however, like those in Paris in November, represent an assault on all of Europe, on our values, on our allies and on our friends.
Our Government must explore ways in which we can not only express our sympathies to the Belgian people, but practical solidarity.