PARIS — What happened yesterday was truly a unique event. We can only hope that, in both Europe and France, it will mark a new beginning. European leaders came to walk alongside President François Hollande and predecessor Nicolas Sarkozy, displaying their solidarity with France after last week's terrorist acts. There were also other noteworthy heads of states present, including those of Israel and Palestine.

This Europe, which is so often criticized for being just a single large economy, demonstrated that it's much more than that. That it must be a lot more than that. Confronted with barbarism, it remembered where it came from. European construction was launched 60 years ago to guarantee peace and democracy. Today, Europe must face up to new challenges, all the while seeing its prosperity undermined.

As Italian Prime Minister Matteo Renzi pointed out, Europe will have to equip itself with new shared instruments to guarantee its security, both at its doors and within its borders. Likewise, all the countries represented yesterday will have to show their determination anywhere and everywhere terrorism takes root, they who let Syria down.

And for France in particular, last week's events are a crossroads, in a country eaten away by doubt and division, caught in an endless spiral of crisis. Yet again, it's in the face of terror and fear that the French remember the values that make France. The incredible international impact of this series of killings surprised the country of Enlightenment. The execution of Charlie Hebdo cartoonists, police officers and other innocent victims has inspired the country. When German Chancellor Angela Merkel, who sees her country torn apart over immigration, says she is impressed by the reaction of the French people, it's not just words.

This exceptional global support requires France to measure up to what it symbolizes: a republic where people from any religion and origin form a pluralistic, secular nation that rejects racism and fanaticism. But getting there will be a challenge. After a regenerative Sunday, there will be a rude awakening. Arguments will resurface. The government and religious leaders will have to meet rising expectations. The imperative of security must lead to effective solutions, to rejecting the demagogical proposals that will undoubtedly flourish. The left will have to be pragmatic and avoid lazy idealism. The right will have to be a constructive opposition force, guarding against extremism.

Are these pious wishes? Exceptional situations require exceptional responses.