Each time there is some new outrage committed by Islamic terrorists, Europeans go through a sort of lobster quadrille. There is immediate anger against Islam and Muslims in general, quickly countered by denunciations of Islamophobia. Muslim clerics will be found who denounce the terrorists as anti-Islamic and liberal Muslims will be produced who demand freedom of speech and the press just as loudly as the rest of us. Indeed, the media will quickly draw attention to the fact that there are Muslim victims too, like one of the policemen cold-bloodedly shot down in Paris. Having bounced around this sounding box the media then draws the lesson that anti-Muslim and anti-Semitic manifestations are all as bad as one another and that being good liberals means that we should all avoid taking any view at all about whole communities and instead treat everyone as individuals. This sounds right and reasonable and all men of goodwill subscribe to such sentiments.

However, the fact that Jews are now fleeing France in exactly the way they fled Nazi Germany in 1933 suggests that this just isn't good enough—not even nearly good enough. Of course, this is not to say that France today resembles Hitler's Germany: the very opposite. It is an unimpeachably liberal republic. But the particular liberal compromise with Islam that it represents is actually having the same results that the Nazis wanted. The fact that all the Jewish victims of the Paris supermarket attack were buried in Israel, not France, is a powerful signal of the mood. Even in death, and even in an Israel continually threatened by rocket attacks, French Jews feel more secure there than they do in France.

The basic sociology of the situation is that there are almost five million Muslims in France out of a total population of 65 million. (In Denmark Muslims constitute nearly five per cent of the population.) As elsewhere in Europe, this population tends only to rise, thanks to a positive natural increase while the host population is declining, and the continuous addition of Muslim refugees and immigrants from Africa and the Middle East. Similarly, Muslims are strongly pratiquant (while the host population is ever more secular), which means that Muslims have a far stronger community sense than other groups and also that they weigh far more heavily than their numbers might suggest in the religious and cultural life of the country. They are also simply far more determined about promoting their distinctive identity than other groups. They want their women to dress differently, they want the sexes to be kept apart, they want Muslim schools and Koranic education and the extremists among them may commit terrorist acts. One could admit any number of Hindus, Buddhists, Confucians or Shintoists to one's country without facing any of these distinctive demands or pressures.

The crude fact appears to be that you can't have as many Muslims as this in France—or even in Denmark, where there has been a growing pattern of Muslim hostility to the tiny Jewish community left there after the Holocaust—without generating pressures which cause the Jews to flee. It will be objected, of course, that the reason for the alienation of many Muslim youths is their high unemployment rate and the poor conditions in the banlieues. That is true enough, but there is no sign at all of these conditions diminishing: rather the contrary. Similarly, the "reason" for the wave of anti-Semitic attacks in France in 2012-15 relates to anti-Israeli feeling provoked by events in Gaza and on the West Bank. (I put inverted commas round "reason" because such events would not cause similar reactions by other groups. Throughout the long struggle for Indian independence, after all, there was no Hindu terrorism in Britain.) But there again, neither Israel nor anti-Israeli feeling is going to go away: everything suggests that Israelis and Palestinians will fight their own Hundred Years' war.