The attacks are gruesome proof that the so-called Islamic State sees the capitals of Europe as soft targets in a hard war. The moment Salah Abdeslam is bundled into a car by police. Credit:VTM The pace has been infuriatingly slow, but the territory IS holds in Iraq and Syria is shrinking under constant US-led bombardment. However, IS is widening its battlefield in a way that brings the war to the heart of the West – first Paris in November; now Brussels in March. "Its brand is brutality," William McCants, a Brookings Institution analyst and author of The ISIS Apocalypse, told The New York Times. "If that's your brand you don't have to exert a lot of control over your operatives, and you can send them off to kill wherever they find the opportunity." The Brussels terror dynamic reveals the clashing imperatives for terrorists and those who pursue them. A group like the so-called Islamic State wants to retain control of the narrative and to keep the initiative – just as security services need to act as quickly as possible on any information extracted from the likes of Abdeslam to head off new attacks. The terror cell wants to drown the story of success by the authorities in capturing Abdeslam with a stunning new show of its capability in causing chaos.

Belgian security agencies were assailed in the immediate aftermath of the bombings. But all of Europe invites attack because of its porous borders; national and branch rivalry and jealousy between the services; and a sense in the smaller countries that it's up to the bigger EU member countries to deal with the security challenges. The blown out facade of the airport terminal. Credit:AP So Belgium was a blessing for IS. It was a logistic and planning hub before, and a bolthole after, the Paris attacks in which 130 people died. And in a Europe already reeling under the weight of a migrant exodus from the conflicts in Syria and Iraq, Tuesday's attacks will prove to be a new challenge to EU cohesion if individual member states conclude that they cannot rely on their neighbours to protect them. An injured woman leaves the scene at Brussels airport, after explosions rocked the facility on Tuesday. Credit:David Crunelle

On Friday, Belgian police were being congratulated for the live capture of Abdeslam, even if he had been hiding in plain sight. But just days later, the country was in convulsions and chaos as a string of suicide and other bomb attacks killed more than 30 and wounded scores more. Shiraz Maher, of the International Centre for the Study of Radicalisation at King's College London, told reporters that per capita, Belgium had the highest number of foreign fighters in Syria of any European country – "more than twice as many have gone from there as from France, and more than four times as many as from Britain". Nam Laachraoui, left captured on CCTV, moments before the blast with two other bombers. Credit:AP The Molenbeek quarter in Brussels is a hotbed of jihadist activity, running a not-so-underground shuttle of fighters to the war in Syria and, before that, to other conflict zones. But by various accounts, Belgian security forces are reluctant to enter Molenbeek. The local mayor reportedly received a list of as many as 80 suspected Islamist militants living in the quarter in November 2015 – it included Salah Abdeslam and his brother Brahim, who blew himself up in the Paris attacks.

If as seems likely, the cell behind Tuesday's attacks is a remnant of the cell that planned the Paris ones, why had Belgian forces not rooted them out? If it was a new group, how could it have outsmarted the authorities when all of Europe, and Belgium in particular, was on such a high alert? But in the wake of the capture of Abdeslam, why was Belgium not on its highest alert? How could the far more sophisticated November attacks in Paris have been planned and resourced from Molenbeek, without the Belgians having stumbled on a clue? Why did it take 125 days to find Abdeslam, when it was known he was lurking in Molenbeek? It must have taken dozens of associates to cover for him – again, why no arrests? More particularly, on Sunday, Belgian Foreign Minister Didier Reynders said that Abdeslam had told investigators that he had been planning fresh attacks in Brussels – so why no investigative follow-through? And how was it that the Paris attackers were able to survive a Belgian security dragnet that, early last year, was supposed to have cleared Molenbeek of its worst jihadist elements? Criticism of Belgian security goes deeper than front-line grunts.

There are accounts of agencies not working together, of failing to make the best use of technology. The government as a whole is accused of dragging its heels – in a country with an estimated 800-plus known suspected jihadists, there are only 1000 civilian and military intelligence officers attempting to counter and corral them. On a more structural social level, critics charge that Belgium can't get it together because it has never met the challenge of reconciling its national and cultural fractures – tension between its French, Dutch and German-speaking communities which lead to political instability. And in the Muslim community there are complaints that Belgian authorities were happy to see hundreds of young men heading off to fight in Syria and Iraq, just to be rid of them. When CNN investigated life in Molenbeek in the period between the Paris and Brussels attacks, Geraldine Henneghien, whose son Anis died fighting in Syria, complained that there was no response from Belgian police when she reported her son's plans. Leading the finger-pointing at security failings in Brussels was the French newspaper Le Monde, which dubbed Belgium "a clearing house for jihadism" on its way to becoming "a nation without a state". In the past, Belgium has had waves of terrorism – in the 1980s and 1990s. It has poor Muslim communities, like Molenbeek, in which recruiters prey on the jobless and the angry. Added to that, as the headquarters of the European Union, any strike in Belgium is a strike against world power structures.

Donald Trump was quick to weigh in, claiming that "more than waterboarding" was the solution to terrorism. But the complexity of the terror challenge, as the Brussels attacks reveal, continues to defy governments in Europe and beyond – and probably requires more thoughtful responses. There were many calls on Tuesday for a new ring of security around airport terminals and metro stations – but this would simply create a new target, as crowds of travellers backed up, waiting to be processed. Aviation security expert Philip Baum told The Guardian: "It's ultimately down to looking for people with negative intent and we have to do that without creating new security hurdles that create new targets, such as checkpoints at the entrances to terminals. "If you look at the Germanwings crash, Metrojet bombing [in the Sinai] or today [in Brussels], people with criminal intent think outside the box – and we need to too." The West needs to do exactly that, because it's how IS operates.

Remember when the US-led coalition started bombing IS targets in Iraq, back in September 2014? IS spokesman Abu Muhammad al-Adnani appealed to its supporters in the West for attacks on military and civilian targets. Loading "If you can kill a disbelieving American or European, especially the spiteful and filthy French, or an Australian or a Canadian, or any other disbeliever," he said in an audio address, kill him in any manner or way however it may be." They're listening; they're acting, shaping a new European normal, as they did first in Paris and now in Brussels.