That the assailant is a foreigner who selected New Zealand as his stage should not diminish our drive to look fully into the circumstances. Selective rationalisations can all too easily take us to desired rather than actual risks of reoccurrence.
The stronger gun control laws and government surveillance review called for by the Prime Minister are useful operational steps for combating future risks. But as terrorist attacks abroad with vehicles used as weapons show, serious harm can still be inflicted by other means.
Speculating about the assailant's mental condition, too, can only take us so far towards understanding how someone inspired by an international network of similar-minded individuals came to carry out this meticulously well-planned act to achieve his warped aims.
To thoroughly identify future risks we must look also at the assailant's stated motives and the wider social and political context. Here, his manifesto cites hateful anti-immigrant, anti-Muslim and white supremacist views. And it connects his actions to global trends like the backlash against immigrants in Europe and "renewal" of white identity in the US.
While the Prime Minister and others are right to emphasise that these extreme views in no way reflect "who we are" as New Zealanders, we should nevertheless consider how well our communities are inoculated from a repeat, perhaps even home-grown, attack.
Here, we must unfortunately acknowledge that several of the same sentiments expressed in the assailant's manifesto are also expressed in various forms by citizens of this country. And although this is by a small minority who usually don't threaten violence, it is nevertheless in our interests to marginalise these views into history.
For just as the divisive rhetoric of Trumpism, Brexit and the like has increased hate crimes elsewhere in the West, expressions of hateful bigotry here at home also create the space for more targeting of minority groups.
Current trends in the West also show us that kindness and decency are not default settings and can erode quickly if not sufficiently protected. So when we stress that this is not "who we are", we should be prepared to also champion why "who we are" is so important.
We should actively make the case, repeatedly if necessary, for decency, kindness and respect whenever and wherever we encounter bigotry or hate, and to explain how these qualities make us a stronger and safer society.
The battle between decency and violent extremism has reached our shores, whether we like it or not. In fact, its seeds were already here. So as we rally around the Muslim community and each other during this difficult time, let us also take an active stand against expressions of hate in all their forms.
For while kindness, compassion and decency stand to ultimately prevail, they will not do so automatically. Instead, we must actively work to promote the values we wish to be the essential elements of "who we are". Or to borrow from peacekeeping again: peace, like war, must be waged to be won.
• Matthew Willis is a former United Nations peacekeeper and political advisor who has worked in or on crises in Afghanistan, Darfur, Nepal, Lebanon and Yemen.
