Mohammed Merah is dead. In France, in the press and in private, there will be much discussion about how many French Muslims share his extremist world view.

But think back to Monday, when the police said they were investigating the Toulouse murders on a twin track, looking for either a neo-Nazi or jihadi. Suppose the murderer had been inspired by Anders Breivik, the same question would be asked: how many Frenchmen share this extremist world view.