In Paris, casualties in a new global war

And so we mourn again. For Paris, again. And this time, for the world as well. Because something has changed.

We thought we knew what war looks like. Not anymore.

It was Friday evening in Paris, the world's beloved City of Light. The warm autumn night was filled with music and sport and celebration. And then it all stopped, shattered by a stunning series of terror attacks.

We were shocked by their size and scope, and by a synchronization we haven't seen since 9/11. We were horrified by the hundreds of people killed or wounded, including at least one American. And we were bewildered at where it all took place. In a concert hall. Outside a soccer stadium. At a restaurant. Venues of entertainment and fun, refuges from the cares of life. And in a neighborhood where young people of many races and religions mingle.

The victims were doing things we all do, things that are supposed to be safe, things that bring us joy and pleasure. And things that, once attacked, leave everyone uneasy.

What happened also must be placed in the context of a world already on edge. The barbarism of the Islamic State, which claimed responsibility for the attacks, has been appalling. It was only 10 months ago that ISIS militants carried out the massacre at the Paris offices of satirical magazine Charlie Hebdo. And what unfolded in Paris followed closely suicide bombings in Beirut and Baghdad that killed dozens more, and the crash of the Russian flight from Egypt ISIS is suspected of causing.

Nations of the West are used to watching and waging war on distant battlefields. Now the conflict has come to us, and it reminds us that danger is present every day in other parts of the world, danger from which millions of people flee.

In New York, we know these dangers as well as anyone -- and we know that in the horror of war all innocent lives taken are equal. We lived through 9/11. We were staggered then by the indiscriminateness of death, just as we are today.

There still is much we don't know. How developed is the network from which this violence sprung? How many were involved in its planning and execution? And it leaves us wondering whether the definition of normalcy in the West will change. Will it now include states of emergency, border closings, lights and sirens, fears and screams?

Those are the hallmarks of war. Any doubts about the nature of this conflict were dispelled Friday night. This IS a war. French President Francois Hollande bluntly labeled it such. Pope Francis said the attacks were part of the Third World War. And the Islamic State itself sounded the alarm, boasting in a communique about having cast terror and horror in the "hearts of the Crusaders." And it promised that "this attack is the first of the storm and a warning to those who wish to learn."

Whether the Islamic State's goal is to evict the West from Syria and Iraq, to create a world caliphate, or simply to sow chaos and confusion around the globe, its tactics must be confronted and stopped. But how? And by whom?

There is a growing consensus that these assaults will not stop until the Islamic State is defeated on its own turf, and that it cannot be defeated by air attacks alone. But whose troops will fight? And how many? Will ending one threat simply give rise to another? It feels like this is a point of change, but the will of nations is fickle and unpredictable, and time erodes urgency.

And yet, it is clear that terrorism has reshaped our world. We were reminded again on Friday night what it feels like when security is replaced by fear, when trust gives way to suspicion, when safety is undermined by doubt. We must make sure that this does not lead to despair and desperation.

President Barack Obama was right when he said this was an attack on all of humanity, and that we all must stand against it together. And we will.

But for now, we mourn. Again.