So we are at war. We have been for more than a year now, ever since Charlie Hebdo and a Hypercacher kosher supermarket were attacked in January 2015. Then in November, more killings at the Bataclan concert hall and nearby restaurants, after an attempted attack at the Stade de France. “We are at war”, the prime minister Manuel Valls declared at the time, and he was right, justifying the state of emergency and the enlarged powers given to state authorities at the expense of private liberties.

Even after all France has endured, this attack is a huge shock | Agnes Poirier Read more

There was little protest, no political squabbling and haggling. These were the days of union nationale, even if the traumatic events of November did not lead to the kind of emotional upsurge that took us to the streets following the Charlie Hebdo killings.

We are at war. We realised it once more in March, when Brussels was hit. There was plenty of criticism about the way Belgian authorities handled the situation until we understood they were attacked by the same people, and were confronted by the same impotence any democratic society faces when trying to fight terror.

Being at war, we know we have to protect and defend our values. When freedom of expression is under attack, as it was with Charlie; when antisemitism becomes a reason to kill, as at the Hypercacher store; when our way of life – the music, the mingling at cafes – becomes soaked in blood; when our police are murdered, as Jean-Baptiste Salvaing and Jessica Schneider were at their home near Mantes-la-Jolie last month.

In Nice, once the Bastille day fireworks had faded in the summer night, 30,000 people were strolling away, and violence struck again. This time, children have been hit. Families have become the target. What kind of rationale can be presented now, what explanation offered to grieving relatives in front of smashed bones, fractured skulls – a white truck driving at speed, zigzagging to kill as many people as possible over a mile-long stretch?

What more can be done in terms of prevention and intelligence?

In the middle of the night, François Hollande announced it was an act of terror, and that the French military involvement in Iraq and Syria would be enhanced. The state of emergency, which was to be lifted on 26 July, will run for another three months. Three days of national mourning have been announced.

The country is in a state of shock. But there is no national unity any more. There are too many questions about the circumstances of the attack. Too much alarm at the lack of proper security. Too much politics too: as soon as the news broke, opposition leaders were at the government’s throat. Alain Juppé, a former prime minister and usually the most sober of our presidential contenders, criticised in very harsh terms the inefficiency of the security apparatus. Nicolas Sarkozy called for a military response. Meanwhile Marine Le Pen calls for more determined efforts to eradicate Islamist fundamentalism, but does not say how.

The truck driver has been identified as a 31-year-old man, born in Tunisia but resident for many years in France, with a police record for petty crime and no terrorist pedigree. His papers were found inside the truck.

For the first time, the government has called upon the “operational reserve force” – 26,000 people, mostly retired military personnel or volunteers without any specific training – to bring some relief to the military and police personnel who are on the verge of exhaustion. Tension was high during the Euro 2016 competition, and the Tour de France is not over yet. Summer holidays have just started.

“We are not done with terrorism,” the French president has said once again, paying tribute to the dead and visiting the wounded. We agree. But what more can be done in terms of prevention and intelligence? How to address the racial tensions in the suburbs? How to tackle the anti-Arab, anti-Muslim sentiment already spreading across social media? We are at war, and we don’t know what victory would look like.