TURIN — France attacked on the night of July 14th, the country's national holiday, Bastille Day. It was not by chance that terrorists chose this night to strike, when millions of French citizens were celebrating the storming of the Bastille 227 years ago, when hundreds thronged the Promenade des Anglais on Nice's beachfront. The terrorists' choice reveals an intent to humiliate France on the night when the country is at its strongest, when it remembers its historic revolution and celebrates its prized liberties, on the glamorous Côte d'Azur that symbolizes France's unique charms.

The jihadists are well aware of the identities and national calendars of the countries they attack, using them as a tool to inflict even greater terror — to have citizens "fear death even when they sleep," as once promised by Abu Bakr al-Baghdadi, leader of the Islamic State terror group (ISIS). Thursday night in Nice, their weapon of choice was a large truck used to plow through unsuspecting crowds. This tactic, used in the past by "lone wolf" terrorists in minor French cities, also bears similarities to the so-called "Car Intifada" launched by Palestinian insurgents against Israel.

If the deadly shootings in Paris last November heralded the beginning of a long campaign of terror attacks on Europe, and the bombings in Brussels and Istanbul this year revealed the existence of a vast network of sleeper cells, then the massacre in Nice implies the terrorists' offensive is now in full swing. If the nations of Europe are to face down this threat, they must come together to integrate their security services and fashion a new doctrine for collective defense.