The centrist front-runner in the French presidential election, Emmanuel Macron, has called on the French people not to succumb to fear and division after the latest attack in Paris.
He has reiterated his campaign pledges to boost the police and military and the intelligence services in the battle to protect society from Islamic extremism.
His sentiments, warning people against intimidation, are noble and his commitment to robust security is welcome. But his reaction to this attack is in a long tradition of such responses to attacks across Europe, that are almost naive.
Of course people should reject racism and fear, and of course the security forces should be bolstered (a notion that is accepted pretty much everywhere outside of Northern Ireland where the authorities seem not to be allowed to get tough with dissident terrorists). But Mr Macron and politicians like him are discussing the symptoms.
It is not enough to make such pledges and to state that Islam is a religion of peace. Certainly the overwhelming majority of Muslims in Britain and France repudiate such attacks entirely, but a radicalised minority do not.
Nations across Europe have already shown the calm repudiation of division that Mr Macron recommends. The general publics in the affected countries seem to grasp that these attacks are still on a small scale, even though they are frequent in number, and so they must be seen in proportion. But people also see that a free-for-all multi-culturalism, that once rejected as racist any notion that people who move to a society should try to integrate with it, has led to problems. A lack of integration is worse in parts of France and Belgium than in the UK, but there is a clear radical Islamic risk in Britain too.
The open borders of the passport-free Schengen area were an experiment that came with wonderful benefits but seem ill-suited to the mass migration and extremist challenges of today. Britain and Ireland stayed out of Schengen and that is one thing we can be thankful for in these difficult days.