A hundred pages into Soumission by Michel Houellebecq the narrator’s on-off sexual partner announces that she and her parents are leaving France for Israel. We’re between the two rounds of the 2022 French presidential elections, with the Front National out ahead in a run-off against the Muslim Brothers; it looks as if the old parties – big centrist machines – are about to be mothballed along with the Fifth Republic.

On its cover at the time of the murders, Charlie Hebdo played up the ludicrous side of Soumission, announcing the stupendous ‘Predictions of Houellebecq the Seer’: ‘In 2015 I lose my teeth. In 2022 I observe Ramadan.’ (A spoiler: clearly the Muslim Brothers are about to win the second round.) Inside the issue, more derision: Nostradamus may have been a visionary but he never won a Goncourt.

Houellebecq said just before 9/11 that Islam was the most stupid (‘la plus con’) of all religions. His remark was probably less incendiary than a depiction of the Prophet, let alone a caricature – a blasphemy that Charlie Hebdo just committed for the nth time in its memorial edition after the murders on 7 January. (The print-run, it’s announced today, will reach seven million.) The conversation in France is stumbling forward. But people are quick to take offence and slow to grasp that they’ve given it. And increasingly the French suspicion of ‘l’amalgame’ is getting in the way.

‘L’amalgame’? A failure, often wilful, to distinguish one thing from another. Calling a person you disagree with a Nazi lays you open to the charge of ‘l’amalgame’. You would, as Adam Shatz has explained, also be at fault if you took Charlie Hebdo, metonymically, to stand for all forms of freedom on offer in the West. Distinctions are far more useful in this simmering crisis than glib associations (‘you’re a Muslim so you must be for jihad’).

But if we rule out all forms of joined-up thinking, the spectacular crimes in Paris and Montrouge are simply expressions of an epic struggle between right and wrong: in the blue corner, freedom of expression; in the green corner, superstition and backwardness.

Here is one ‘amalgame’ we should not be shy about. Jihadist violence has a domestic context. In France, it’s the marginal status of Maghrebi immigrants and their descendants, and the burden of suspicion that falls on them whenever things get tough. There are too many of them; they fail to grasp Republican values; are we to blame if they can’t find work or take up disproportionate space in our prisons? They are hollowing out the Republic by failing to ‘assimilate’, so our only choice is to twist their arms, which is why we banned the hijab in 2004 in Republican spaces like schools and why we banned the niqab and the burqa in any public place in 2011. These self-portrayals hurt us so profoundly that we’re ready to ostracise, isolate and fine offenders.

Here is another. Jihadist violence also has a global context, even though it’s mostly European citizens who commit atrocities in European countries. Non-Muslim majorities worry that Islam is already past the gates (they thought the same about the Balkans in the 1990s). But from a ‘Muslim’ perspective, the map of influence looks very different. To the east it’s a morass of foreign intervention, military occupation, resource extraction, drone wars, industrial levels of torture and internecine strife, much of this since 2003, when Bush and Blair turned the international order inside out like a used sock and tossed it under the bed. Those who doubt the connection between jihadist activity in the West and the projection of Western power in Muslim-majority countries could ask themselves why Western intelligence services take a different view.

It isn't just enraged pizza delivery men like Chérif Kouachi – ‘radicalised scum’, Marine Le Pen called them last week – who commit jihadist atrocities. Architects, law students and teachers were in on the act on 9/11. A big, unwieldy alliance across cultures and faiths in France that might isolate jihad looks unlikely. For one thing, Republicanism is held up as a non-negotiable monoculture; for another, there’s too much anger and incomprehension, feeding on social inequality at home and chaos in much of the Muslim world. Whatever novelists and cartoonists do, they’re not in the business of fostering big, unwieldly alliances. This is the time of the emerging, disciplined party, untarnished by a record of government, that cultivates its following in the shadow of insecurity. Never mind Houellebecq’s premonitions; Marine Le Pen is already forecasting success in the departmental elections in March. And so are the pollsters.