It appears that the brutal attack on Charlie Hebdo in January was just a curtain raiser, a taste of what was to come. And the chilling prospect after Paris's latest night of death is that there will be yet more to come in the same vein.
And more for other western capitals too.
None of us are immune from the brutal logic of Islamic State (IS).
We are all to learn what it has been to live in Baghdad or Beirut. Or Belfast in its deadliest times.
Eighteen dead in France in January, and at least 128 this weekend.
Soul-searching
There will be much soul-searching now about whether France had done enough to prevent this massacre – but that deep psychological need to find someone to blame can be illusory.
Ultimately, the hard truth that we must all also face is that an open and democratic society is inherently vulnerable and can never completely prevent such outrages without abandoning its fundamental values.
And that is a road we must not let IS – as it would wish – tempt us down.
IS’s brutal attacks are in reality of little military strategic significance. They are not capable of creating a new balance of military power, of winning battles or seizing ground.
But they are of huge political significance – to paraphrase Clausewitz, politics is war carried on by other means.
Fear, horror, confusion
Their purpose is entirely psychological and political, to create fear, horror, confusion and an illusion of chaos.
It is to provoke a destabilising reaction – unsettling and questioning in the public, and repressive in states that their propaganda revels in.
Britain and France are currently debating legislation to increase online surveillance. New police powers will undoubtedly be sought.
Such measures and other new tools for the state's armoury may be hard to resist politically at this time. But they will be manna for the recruiting sergeants of IS in the banlieues of Paris among their deeply alienated young migrants. We must hasten softly.
And there is a real danger that the attacks will also fuel the rise of the far right, notably the Front National.
The temptation by governing parties to borrow their easy slogans to curtail their advance must be resisted.
Universal values
US President Barack Obama has rightly described the Paris outrages as attacks not just on the French but "on all of humanity and the universal values that we all share".
In this he speaks for all of us, echoing those earlier declarations of "Je suis Charlie!" that rang around the world .
And such sentiments are not just abstract expressions of political solidarity – we feel the pain, shock and anger of our French cousins as if they were our own.
We know and love the streets of Paris, its cafés and theatres.
Friendship and history
We are bound by a thousand ties of friendship and even kinship, history and culture.
Only last week a French minister visited Dublin to honour the thousands of Irishmen who died on the Somme 100 years ago.
We feel your pain.