But what everyone should know is that it represents the last chance to defeat by diplomacy alone the adventurism, recklessness, and bellicosity of the Kremlin.

In other words, the West needs to be willing to look at things head on and stop doing what it has already done far too much, which is to reverse the roles.

It is Vladimir Putin, and Putin alone, who has taken the historic risk of confronting his European neighbors. 

It is Putin, and Putin alone, who, by sending his planes to skirt the airspace, yesterday of Estonia and Poland, and today of France, is trying his hand at a war of nerves between powers, that, as his press takes a perverse pleasure in pointing out, are sometimes nuclear powers. 

It is Putin, and Putin alone, who, for the first time since the Cold War, has made the momentous decision of landing troops at the threshold of Europe try to alter by force the borders of a country that is a keystone of the collective security architecture that keeps the peace among peoples. 

It is Putin, and Putin alone, who, for the first time since the Second World War, has retrieved from the museum of political horrors the sadly famous themes of linguistic nationalism (according to which a Russian is someone who speaks Russian; a German someone who speaks German), which we thought had been forever discredited by the distant matter of the Sudetenland and the Anschluss.

And it is Putin yet again who, by clearly aiding every racist and anti-Semitic party on the continent, by supporting, even financing, the likes of Podemos, Syriza, and the Front National, the avowed goal of which in every case is to destabilize the European Union and its rules, by flaunting his alliance with the Hungary of Victor Orban that has become the weak link in the Union, by these acts, and others, it is indeed and undeniably Putin who is interfering in Europe’s affairs; it is indeed and undeniably the revanchist Putin who, as if nursing an old and stubborn grudge, as if holding Europe responsible for the fall of the Soviet Union (which Putin has described as “the greatest geopolitical catastrophe of the twentieth century), seems intent on undermining Europe’s foundations. 

And as for the arguments routinely advanced by the adherents of cowardly appeasement, it is striking how much they, too, are drawn from the arsenal—a rhetorical arsenal for the time being—of Putinism. 

Ukraine was historically part of Russia? By occupying the Crimea and then Donbas, the heir of Nicholas I and of Stalin is merely recovering what had been Russia’s? Beyond the fact that this argument is historically false and that the Russian nation state is no older than the Ukrainian, the argument, were we to accept it, could be applied tomorrow to various pieces of the Baltic states and to Poland. Inversely, it could even permit the Poles, who were in Moscow in the early seventeenth century, to stake a claim to the Russian capital. 

By behaving as it has, is not Russia simply reacting to the tacit “humiliation” that Europe has inflicted on it for 20 years? Is it not understandable that Russia should push back against its “encirclement” by the “empire”? That argument makes no sense either. Indeed it appears quite grotesque if one recalls the persistence with which Russia was invited to join the Partnership for Peace (1994), the Council of Europe (1996), the OCSE’s Charter for European Security (1999), and the NATO–Russia Permanent Joint Council (2002). It becomes positively indecent if one remembers the scrupulousness with which the West has refrained, since the Wall fell, from basing foreign forces in the former East Germany and from deploying in Poland long-range ballistic missiles that might offend Moscow, even while selling Russia Mistrals and closing the doors of NATO to Georgia and Ukraine.

In short, in Ukraine Europe faces a situation not of its choosing, to say the very least. 

And, in the face of this very serious crisis carefully orchestrated by the Kremlin, it had a choice of two possible attitudes. 

Either it could fall back and, yielding to the partisans of “Eurasia,” an idea conceived and presented as a geopolitical and ideological alternative to the European Union, stake its honor, lose its soul, and embolden the forces both within and outside the Union whose sole goal it is to see Europe fall apart. 

Or it could react and face up to the menace that, beyond Sebastopol and Lugansk, threatens the dream of lasting peace of the Kantian philosophers, a dream realized by Europe’s founders, from Konrad Adenauer and Robert Schumann to Helmut Kohl and François Mitterrand—and, in facing up to that menace, come resolutely to the rescue of a Ukrainian nation that has become the sentinel of democratic Europe. 

Largely at France’s urging, Europe chose the second response. 

It was the wise choice, provided one keeps in mind that the diplomatic option, while by far the most desirable, is obviously not the only one and that we may have to resolve, if we cannot stop Putin, to give Ukrainian President Petro Poroshenko the military means he needs to credibly defend his country. 

Bernard-Henri Lévy is one of France’s most famed philosophers, a journalist, and a bestselling writer. He is considered a founder of the New Philosophy movement and is a leading thinker on religious issues, genocide, and international affairs. His 2013 book, Les Aventures de la vérité—Peinture et philosophie (Grasset/Fondation Maeght), explored the historical interplay of philosophy and art. A play, Hotel Europe, performed in Sarajevo, Venice, Odessa, and Paris in the latter half of 2014, is a cry of alarm about the crisis facing the European project and the dream behind it. (This opinion piece was translated into English by Steven B. Kennedy)