On Thursday night, for the third time since January 2015, President François Hollande was faced with a mass murder on French soil. An ashen-faced Hollande, almost looking like a broken man, appeared on television on Friday at 4am and declared: “This is undoubtedly a terrorist attack; the whole of France is under the threat of an Islamic terrorist attack”.

France has certainly been the target of terrorist organisations of late but it was nonetheless surprising to hear him jump to conclusions. As he spoke, the police hardly knew the identity of Mohamed Lahouaiej-Bouhlel, the 31-year old man who killed 84 people. What is more, no obvious links to radical Islam had been established by the police. The possibility of a lone-wolf attack could not be dismissed out of hand (and it still can’t as I write).

Hollande’s credibility and authority have almost totally evaporated only 10 months before the next presidential election. He is not only the most unpopular president of the fifth republic, he is also loathed by many of his former supporters on the left. But the collapse in his support and the acts of terror of the past recent years have to be placed in a wider, more troubling context. The old party system is threatening to collapse imminently. The problems therefore run much deeper and are more serious than the fate of a lame-duck president.

During Hollande’s term in office,the political landscape has been profoundly transformed. His actions have had a negative impact on the left in general: the radical Left Front, a coalition of parties to the left of the Socialist party, is being sucked into the abyss together with the Socialists. Nicolas Sarkozy’s Les Républicains party is doing marginally better, but only because it has not been at the helm in the past few years.

There is one victor and a political force that goes from strength to strength, though: Marine Le Pen’s Front National. Although Le Pen mostly keeps quiet these days, her political future looks bright as all opinion polls predict that she will qualify for the second round of the forthcoming presidential election.

The 2015 Charlie Hebdo and Bataclan shootings triggered an outpouring of collective grief and cemented national unity. For a short period at least, Hollande benefited from this “sacred union”: left and right, almost all French people rallied around the “Je suis Charlie” watchword.

It is unlikely that history will repeat itself a third time. The Nice atrocities could herald a reaction of public defiance to Hollande and to mainstream politicians, as well as start a process of political disintegration. This bleak scenario would play into the hand of the extreme right and would further strengthen it. Security chiefs are even concerned about reprisal attacks from the far right on minority communities.

The timing and circumstances of the Nice killings were particularly disastrous. It happened on Bastille Day, which is more than a national celebration or even a tribute to the 1789 revolution. For most French people, 14 July (as we simply call it) is the festive enactment of republican France and of its motto: “Liberty, Equality, Fraternity.”

Those are enticing objectives, but for many French people, the combination of economic hardship, political instability and physical insecurity (due to the now regular terrorist attacks) has deeply undermined France’s republican ideal. There is no liberty when people fear for their lives whenever they go about their daily business; there is no equality when the young have no faith in the future; and there is no fraternity when the Muslim population, an important and large component, is discriminated against and regarded as the “enemy within”.

This time, there will be no national unity. Politicians from the left and the right have, for the first time, called to account Bernard Cazeneuve, the interior minister. Questions have been asked about the security failure that enabled Lahouaiej-Bouhlel to gain access to the Promenade des Anglais and then drive into the crowd.

More broadly, it is the state of emergency that is being challenged by mainstream political voices. François Hollande had announced hours before the attack, in a televised interview, that the state of emergency would not be further prolonged. The Nice events made him operate an instant U-turn: it will indeed be extended for another three months.

The right and far right declared that the extension was a cosmetic measure to reassure the public. Les Républicains MPs accused Hollande of failing to implement enough effective and intelligence measures and argued that French intelligence has been inept at neutralising the terrorist threat. Instead, the left insisted on the uselessness of the state of emergency. It points out that it did not prevent another attack, nor did it stop more French youngsters from supporting Isis or help sort out the refugee problem. The left argues that the state of emergency has essentially enabled the government to curb important civil liberties. (These include restrictions on the right to demonstrate, an increase in house raids and searches without a warrant, power of officials to place people under house arrest, militarisation of the public space or police brutality against demonstrators.)

A progressive and effective anti-terrorist strategy would make different choices: it would put an immediate end to France’s military interventions overseas, as, it can be argued, they only foment political instability and sustain the refugee crisis. It would abandon the neoliberal and austerity policies that have impoverished the working-class populations (which include immigrants and their descendants). It would finally train a police force to protect and serve the people and not, as is generally the case at present, to repress members of the ethnic minorities and behave in an arbitrary manner.

Following the killing, the French president’s first major announcement augurs badly for the future: “Nothing will make us yield in our will to fight terrorism. We will further strengthen our actions in Iraq and Syria. We will continue striking those who attack us on our own soil.” Yet the link between Lahouaiej-Bouhlel and Isis has not been established. It could be that the perpetrator acted alone: the police don’t know of any affiliation with any terrorist organisations. The murderer did not have any religious identification; he drank alcohol, took drugs and had a record of violent acts, notably against his former wife. This could be the terrifying story of a disenfranchised petty criminal who went mad and decided to take a revenge against society. In short, it could be an act that resembles that of Omar Mateen in Orlando.

Nice has the reputation of being one of the “safest” cities in France: the mayor has installed more than 1,000 CCTV cameras across town and it has one of the greatest number of municipal policemen in France. Nice is also a hotbed of hard-right politics: race relations are tense and Islamophobia is rampant. Should one be surprised that this appalling event took place in a city that encapsulates all the major social tensions and inequalities in contemporary France?

Philippe Marlière is professor of French and European politics at University College, London