The terrible racist murder of schoolchildren in Toulouse has shocked France.
With just five weeks to go, speculation has immediately begun about how the shootings will affect the French Presidential election. The snapshot view seems to be that the Toulouse shootings may well have "turned the race upside down". The National Front claims that its campaign against Islam has been "vindicated". The French media is speculating that the event may have given struggling President Sarkozy his comeback chance. Perhaps it will, though the economy was still yet prove the decisive factor in May.
If the Toulouse killings do turn out to change the course of French democracy, that ought to trouble us as democrats. Why should the identity of a violent murderer decide a major democratic election?
On Tuesday, most speculation suggested the gunman might be linked to extremist white racist groups. Yesterday, it became clear that the gunman was an Islamist extremist, reported to have been broken out of the Kandahar prison in Afghanistan by the Taliban, and who had been on the radar of the French security services for some time.
Had the killer been a white fascist, the Sarkozy campaign would have been criticised for his tough campaign rhetoric, and accused of stoking a violent atmosphere. Because an Islamist was responsible, some Sarkozy supporters now suggest that this vindicates his tough line, putting Halal meat at the centre of his campaign.
That pattern of news from France offered the precise mirror image of the situation after the massacre in Norway last year. On that occasion, there was an early assumption that the bombs and shootings might be the work of an extremist Islamist group. It then transpired that the killer Anders Breivik was motivated by an extreme and warped far right ideology about protecting Norweigan society from the threat of multiculturalism and Islam.
Of course, who is responsible for an atrocity is an essential question, both to stop the killing spree in the first place, and to look at the lessons for intelligence and policing, and broader counter-terrorism efforts.
We ought to have a similar reaction to such massacres, whoever perpetrates them. Yet it is not always clear that we do.
In a strange way, I felt relieved that Anders Breivik turned out to have the particular hateful motivations that drove his killing spree. It does seem likely that Norweigan politics today are probably different because Breivik was the killer. The terrible event ultimately seemed to have a unifying and moderating effect on political discourse in Norway, when it might have catalysed an angrier and more rejectionist approach had the extremist cause behind the shootings been different.
The crimes are no more or less terrible, whoever has committed them, or whatever cause they purport to seek to further. Entire groups of the population - whether French Muslims, Algerians or the white majority population of Norway - are not responsible for the acts of an extreme minority, though they do share a responsibility to help root
out the extremist ideologies which can support such killings.
Different extremist ideologies present a threat to democratic values.
The uncomfortable thought that the whole nature of a society's politics and discourse can be foundationally affected by factors - including luck - which determine which extreme plots and actions succeed or fail.
We risk telling ourselves that the right response to acts of terror and violence is to not let them change the nature and values of our society - yet responding very differently as a result of them.
If we do not want extremists like Marine Le Pen to exploit such a tragedy, then we should be hearing similar voices in similar volumes speaking out, whether the hate-filled assassin was Anders Breivik or Mohamed Merah.
If enough democrats are clearly fully committed to arguing against all forms of extremism, whether it is anti-semitism, Islamist terrorism, or nativist racism targeting ethnic minorities, or Muslims, then the extremist exploitation of the grievances arising from any particular case becomes less effective.
There remain arguments for and against France giving the next Presidential term in the Elysee to Socialist challenger Francois Hollande, or to the incumbent Nicolas Sarkozy - just as there were last week.
Whatever the electorate decides, we should all hope that the election is not decided, nor excessively influenced, by the hateful murders in Toulouse.
Follow Sunder Katwala on Twitter: www.twitter.com/sundersays