Terrorists are weak

treat them as exceptions to the normal rule of human co-operation and mutual aid.

There is a certain sense even in President Trump’s declaration that terrorists are ‘‘losers’’. They are not martyrs whose names we should remember, but murderers who should be punished according to the usual rules of law, then forgotten.

Western societies must at the same time continue to reach out to Muslim communities everywhere. Trump, who as a presidential campaigner sought to make Islam the enemy, now as president seeks to build fences with Muslim countries. He is trying to undo some of the damage he has already done. In this he is absurdly inconsistent, praising his Saudi hosts, whose Wahhabist tyranny has inspired many terrorists, including those of 9/11, while blaming his traditional foe of Iran.

But perhaps Trump has given up scapegoating Muslims in general, although his campaign to stop immigration from a range of Islamic countries remains stalled in the courts instead of formally abandoned.

Trump has also abandoned the American attempt to remake the Middle East, which has greatly boosted world terrorism. George WBush’s invasion of Iraq was in that sense fatally counterproductive, leading both to Isis and a wider outrage among alienated Muslims throughout the West.

We don’t yet know why the Manchester perpetrator did what he did or how much support he had. Isis has claimed responsibility, but in what sense?

The main lesson of terrorism is that in the end it is a weak force that does not threaten the society in which it occurs – unless that society colludes with the terrorists by over-reacting. If we allow terror to give more power to the demagogues among us, the terrorists win because the demagogues will destroy our liberties and rights.

New Zealand has so far avoided terrorism, partly no doubt because of its global insignificance. But here too there are demagogues who would try to make capital out of terror. We must resist them.