Within thirty minutes of Friday’s tragic events in Sweden, the speculation had started. I typed “Stockholm attack” into Twitter and my screen was filled with bulbous green frog symbols, the avatar of choice for the nationalist alt-right movement.

“More innocent European lives sacrificed on the altar of diversity. DAMN YOU, MIGRANTS!!!” read one. Another shared graphic photographs of the bloodied bodies of victims lying on a Stockholm road – against the wishes of their families. The caption read: “Stockholm terror attack victim. This is what the roaches from the Middle East are causing.”

The bleeding-heart liberals were also out in force, but for the other side. Many tweets reassured us that the attacker (about whom we still know very little – one suspect is in custody and no one’s claimed responsibility) must be mentally ill, while others rushed to assure us that this was “nothing to do with Islam”, before he’d even been named.

In fact, we know very little about this attack. The suspect who has been held in custody is said to be from the Muslim Central Asian nation of Uzbekistan, which undermines both the current nationalists’ obsession with Middle Eastern refugees, and the Left’s determination to avert their eyes to a pattern of Islamist violence.

Swedish detectives make arrest after Stockholm truck attack

What we can anticipate though, is that just like the other recent terrorist attacks in Europe, Friday’s tragedy will be seized on by every political movement with an axe to grind. Yet one thing all factions often have in common is the idea that countries who find themselves victims of terror have only themselves to blame. Nationalists will claim this is a result of weak borders and generous refugee policies, while liberals will argue this new wave of terror is the legacy of ill-advised and unjustified interventionism.

Any terrorist attack is always going to be politicised. Sweden has led Europe in its compassion and openness to refugees – and as a result has been the subject of derision by white nationalists, especially those in America who see European multiculturalism as a symptom of the Old World’s endemic weakness and fading glory. Since 2014, under Stefan Löfven’s premiership, it has been a beacon for the European social democratic movement, who will be deeply invested in dismissing any sense of social unease.

Sweden has sent troops to none of the Middle East’s recent wars (it is not even a member of NATO). It has sent massive amounts of foreign aid to Muslim countries and others suffering devastation.

When airplanes hit the twin towers on 9/11, I remember a classmate turning to me with all the knowingness of adolescence, and telling me, just after 3,000 people had been killed: “Well, now America will have to accept that its foreign policy has caused others great suffering.” After the London attacks of July 2005, a neighbour looked me in the eye and told me: “Well, we had it coming after what we did to Iraq.”

Perhaps it’s easier to impose a narrative, however bitter, than to admit that some things don’t have a simple explanation. The world is full of geopolitical tension, and of unstable angry young men with a grievance.

In pictures: Stockholm truck attack Show all 15 1 /15 In pictures: Stockholm truck attack In pictures: Stockholm truck attack 3 people dead when a truck crashed into Ahlens department store in central Stockholm, Sweden Rex In pictures: Stockholm truck attack People were killed when a truck crashed into department store Ahlens on Drottninggatan, in central Stockholm Reuters In pictures: Stockholm truck attack Special Police forces work at the scene where a truck crashed into the Ahlens department store at Drottninggatan in central Stockholm Getty Images In pictures: Stockholm truck attack Woman is assisted at the scene after a truck crashed into an Ahlens department store in Stockholm Rex In pictures: Stockholm truck attack A policewoman in a gas mask operates at the scene where a truck crashed into the Ahlens department store at Drottninggatan in central Stockholm Getty Images In pictures: Stockholm truck attack People react at the scene where a truck crashed into the Ahlens department store at Drottninggatan in central Stockholm Rex In pictures: Stockholm truck attack Reports say three people have died after a truck crashed into an Ahlens department store in Stockholm Rex In pictures: Stockholm truck attack Armed police operates at the scene where a truck crashed into the Ahlens department store at Drottninggatan in central Stockholm Getty Images In pictures: Stockholm truck attack People react at the scene where a truck crashed into the Ahlens department store at Drottninggatan in central Stockholm Getty Images In pictures: Stockholm truck attack Emergency services close to the scene of an incident in Drottninggatan, a street in the centre of Stockholm, Sweden Lasse Gare/PA Wire In pictures: Stockholm truck attack Passers react at the scene where a truck crashed into the Ahlens department store at Drottninggatan in central Stockholm Getty Images In pictures: Stockholm truck attack People killed in incident when a truck was driven into a department store in central Stockholm Reuters In pictures: Stockholm truck attack Police officers work at the scene where a truck crashed into the Ahlens department store at Drottninggatan in central Stockholm Getty Images In pictures: Stockholm truck attack A general view shows a Ahlens department store after a truck reportedly crashed into it, at Drottninggatan in central Stockholm, Sweden EPA In pictures: Stockholm truck attack A view of a street after a truck reportedly crashed into a department store in central Stockholm, Sweden EPA

Yet we should fight the forces of fear by taking some comfort from what we know. The new terrorist weapon of choice, the heavy-duty truck careening around heavily populated pedestrian areas, strikes terror into the heart. Its victims are random – they could be any of us, strolling around our favourite cities. But they are also containable.

When an attacker struck Westminster a fortnight ago, I was amazed by the number of messages I received from friends around the world, checking that I was OK. The deaths of four civilians and a policeman were a tragedy for their friends and families. But London is a city of nearly nine million. Statistically, anxiety is misplaced.

Those wishing to harm us have been reduced to the most opportunistic and low-tech of techniques. The Stockholm attacker hijacked a truck owned by a Swedish brewing company, as its driver made a delivery and neither he, nor Westminster’s attacker, seem to have been able to get hold of a gun. That in itself should remind us that most of the time, law-enforcement and the security services are doing a remarkable job. The impediments we have in place to large scale violence are working.