The horrible news of the bombing in Manchester makes me (and many people other people) ask "why?" I mean: why do they do it? And what do they hope to achieve?
Violence is one means among many for achieving aims. It is not always unsuccessful: it was not candlelit vigils and singing "Imagine" that ended Nazi-ism in Germany.
Irish Republican terrorism - a policy of violence in support of well-defined political ends - achieved some success. Northern Ireland is now in a constitutionally anomalous position in which the supporters of violence are in effect guaranteed a role in the exercise of power in the Province in perpetuity, while the great and the good on the mainland fret in the meantime that Brexit might have dangerous consequences in the island of Ireland. That is to say, violence achieved something.
"The Arndale was the scene of the city's last big terror attack - in 1996, when the IRA totaled it. Two hundred people were injured, but nobody died ... A few weeks ago the BBC reported that "approximately 850 people" from the United Kingdom have gone to Syria and Iraq to fight for Isis and the like. That's more volunteers than the IRA were able to recruit in thirty years of the "Troubles", when MI5 estimated that they never had more than a hundred active terrorists out in the field."
That's from here. It's Mark Steyn and recommended, but be warned.
So, taking Irish Republicanism as the starting point, what could the new terrorists hope to achieve against the British state, given that there are more of them and they are more violent? (There is of course a difference in that the new terrorists are far more international than the IRA. But, equally, so are their targets and the forces ranged against them. I'll assume that the net effect is broadly neutral.)
Let's leave aside the fact that suicide bombers die. There are people behind them who incite, control, direct, inspire, prosyletise, etc etc. Those people do not die. They have aims and they try to achieve them. What are they hoping for?
There has already been marked success for such people in the fields of depiction of the Prophet Muhammed and general blasphemy laws. Those cartoons don't get published now. Have you heard the one about the priest, the rabbi and the imam? Me neither. And have you tried getting funding for "Koran", the guaranteed smash-hit sequel to the hilarious musical comedy "The Book of Mormon"?
But apart from that, what are they trying to do? And why? In foreign policy, Britain isn't the main target anyway, and Britain is tiring of wars in the Middle East because of the violence over there, not because of the violence over here. I can't see any clear strategy there.
The other area in which I can think of some success is the steady erosion of support for the State of Israel in polite society. But I hesitate to say that the terrorists have had much impact on that. Newspapers can publish pretty robust pieces on both sides of any argument about Israel, and my guess is that 100% gentile dinner parties can still just about tolerate a full-throated defence of Israel. The terrorists are swimming with the prevailing congruent tides of anti-Zionism and anti-Semitism, but I don't think they are causing them: the mood is just too different from that relating to blasphemy.
Which just leaves me with the question I started with. Why? Is there an alternative explanation to Steyn's?