The car bomb attack in Derry on Saturday night sent a shudder right across this island far greater than the physical impact of the bomb.
That, of course, was the intention of the terrorists.
Those old enough to remember the last time anti-democratic terrorism split so much blood on this island recoiled in horror and disbelief.
No other reaction is possible.
Any sane, rational person must have wondered how anyone, no matter how unhinged, radicalised or indifferent to the realities of today’s Ireland, all 32 counties of it, imagined that there is any sort of mandate, any sort of justification for such an attack.
That police believe dissident republican group, the New IRA, was behind the attack is more than disturbing and it will again, as was the intention, divide communities trying to build a better future.
Solidarity, a renewed solidarity, is the very best response.
There can hardly be a more powerful, more pressing argument for the North’s political parties to reopen Stormont, so the political vacuum beloved by terrorists might be ended.