The risk, as is usual after a jihadist attack, is the destructive feedback loop that it creates. It is never just one individual that death cults seek to kill. Their aim is to foment hatred. Already, the French government has announced plans to deport 213 foreigners on a watchlist. Marine Le Pen’s National Rally party, and other rivals to Mr Macron’s right, will push him to go further, encouraging the public to salve its wounds by demanding a collective punishment and stirring up hostility to refugees and migrants.
The priority will be to track down any accomplices or supporters of Mr Paty’s killer. But Mr Macron must not allow his anti-extremism policies to be derailed by psychopathic ideology. He was right to say recently that the challenge is “to fight against those who go off the rails in the name of religion” while protecting other French Muslims. It is tragic that the events of last Friday have made that difficult task even harder.