There is a peculiar horror in the attack in Nice which has killed at least 84 men, women and children. The weapon, the target and even the place might have been chosen to maximise the damage caused to the web of trust in one another’s intentions that sustains civilisation. Though we don’t know for sure whether this was a deliberate act of terrorism it is possible that all were deliberately chosen with this in mind. Although many attacks are carefully planned, others arise spontaneously when local or personal grievances are given a global habitation and a name by jihadi ideology. That sort is almost more frightening.

The victims, as so often in these atrocities all around the world, were entirely innocent people, often whole families, caught up in a moment of celebration, one of those times when everyone in the crowd seems united in a common determination to enjoy the moment until the unthinkable violence strikes. Whether it is the Shia crowds celebrating the end of the Ramadan fast in the recent Baghdad bombing (which killed 156), concert-goers of last autumn’s atrocity in Paris, or the 74 Christians celebrating Easter in a park in Lahore in April the intended message is always the same: that nowhere is safe and no one can be trusted.

The weapon, too, though it has never been wielded to such deadly effect, is one that maximises the distrust and fear that these attacks intend. A truck on the streets is about as normal and everyday a sight as can be imagined. Of course there are no physical barriers to stop it from mounting the pavement but the restraints of civilisation and of sanity which we rely on make it almost unthinkable that this will happen.

War tears all restraint away. In war everything is a potential weapon and unexpectedness can make weapons more deadly. The use of civilian aircraft in the 9/11 attacks in the US is only the deadliest example of this and the disruption and loss of innocence they caused to all civilian air travel since then one of the minor victories of Osama bin Laden.

Even the city of Nice is one of the most vulnerable places in France to this kind of attack, not just because of the presence of large crowds on a road which we have been suddenly forced to see as hideously exposed, but because of its already divided politics, with a strong Front National vote which this atrocity will do nothing to diminish.

There is no guarantee possible that such an attack will not happen again. It may very well happen in Britain. We have been lucky here and not all our luck has been earned. In any case, the enemy need only be lucky once, whereas we must be lucky every time. Nonetheless, there are some aspects of French security that must be improved. It’s worth noting that the French state has at its disposal electronic powers that exceed anything that British governments have even asked for: the security services can bug and hack almost anyone they want without applying to a judge, as well as reading all their emails and keeping track of whom anyone is in contact with, where, and when. None of this prevented the horror in Nice. In part this may be because of the lack of co-ordination among different agencies, both within France and across Europe as a whole.

Essential information never reaches the people to whom it has meaning. It may also be a product of the widespread mistrust with which the French police are regarded by disaffected Muslims. Effective policing depends on human intelligence (a nicer way of saying “informers”) but without trust there will be no intelligence. To build such trust takes longer than sorting out conflicting bureaucracies, and is much more difficult, but at least as essential.

France, and Britain too, is under attack from an apocalyptic blend of politics and religion. The dreadful simplicity of war can make use of every kind of human material, from the cold and rational planner to the angry criminal thug or the psychologically disturbed. There is no single jihadi type any more than there is a single route to radicalisation, something that makes the task of the security services much harder.

The challenge to our values is at the same time political, religious, military and social. So must the response be. This has implications that go beyond politics or security policies. Acts of war like the atrocity in Nice are above all affronts to the decency that all human beings have in common: as ordinary unheroic citizens we can stand in solidarity with the ordinary citizens of Nice and share small acts of common decency with our neighbours.