France was struck by yet another attack this week, the third large-scale strike in a year and a half.

This one involved not bombs or guns alone, as in attacks in Paris last fall on a music hall, stadium and other sites. It was more deadly than the one before that, in the offices of the satirical magazine Charlie Hebdo.

Instead, on Thursday night, a truck plowed through scores of people celebrating Bastille Day on a beachfront promenade in Nice, zigzagging to hit more people. The driver ultimately exited and then fired a gun, according to witnesses.

The truck was filled with weapons and grenades, according to French officials, who called the attack an act of terror. The killer was identified by authorities as a Tunisian-born delivery truck driver who had moved to southern France and reportedly became a citizen through marriage. His motivation was not immediately known — reports indicated he might have been upset his wife left him — but some facts were clear: Body bags again littered a once peaceful street. A little girl’s doll lay next to her body. More than 80 were dead.

Once again, we will argue about adequate responses, about what is to be gained from calling something radical Islam and what role that ideology plays, if any. Before those details emerged, leaders worldwide were making the link anyway.

We also will debate the relative attention paid to attacks on this scale. They have occurred in Bangladesh, Saudi Arabia and Iraq in recent weeks, to muted outrage here at home and less saturation coverage. The attack was thousands of miles away, but affected American lives — a father and son on vacation, now dead. The ordinariness of the weapon tugs at our fears. How do you stop a truck? How do you avoid being in a crowd?

There is an undeniable desire to do something, which leaders around the world have struggled in the past days to convey — something between thoughts and prayers and acts of war. But really, no president or foreign minister or candidate knows how to prevent attacks like this wholly and immediately.

We know already the things we shouldn’t do:

n Use an attack as an excuse to demonize whole populations or deal in generalities, which only antagonizes attackers of any stripe.

n Retaliate hastily for action’s sake and pull ourselves further into a widening web of violence with ill-considered effects.

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n Close our borders and hearts, and ignore the effects of terrorism, here and in other places that get less attention.

Thursday night, French President Francois Hollande extended the state of emergency that had been nearing an end as the Paris attacks receded. The emergency continues.— The editorial board