Paris France is burning, and Bernard-Henri Lévy is watching with anguish.

Since Sept. 16, when riots began, France’s cities and streets have been a stage for arson, looting, vandalism and antisemitism, accompanied by attacks on policemen and firemen. But nothing has broken Mr. Lévy’s heart more in this month of moral meltdown than the torching on Oct. 17 of the town hall in Limoges, 250 miles south of here.

“For French people who do not believe in heaven, the fire at Limoges is a kind of secular counterpart to the fire at Notre-Dame in Paris,” Mr. Lévy says, referring to the destruction of much of the storied cathedral seven years ago. “When the dome of Limoges town hall went up in flames and came crashing down, it was not just a roof that collapsed. A little of the soul of France was burning before our eyes.”Like a church, a town hall, or hôtel de ville in French, is a “common home where citizens marry, vote and honor their elders,” Mr. Lévy says.

“One of the Republic’s cathedrals was going up in ashes and smoke.” (A far-left agitator has been arrested as the suspected arsonist.) Mr. Lévy, 77, is the author of 50 books and the maker of a dozen documentary films. He is known as a philosopher, which in France means a public intellectual, not necessarily an academic specialist, and is familiar to readers of these pages for his passionate dispatches from war zones in Ukraine, Nigeria, the Middle East and elsewhere. He was expecting to spend the fall plugging his latest book, “Mémoires provisoires,” or “Provisional Memoirs,” which was published in France last month.

But with his country teetering on a cliff, Mr. Lévy’s attention is elsewhere. “You can sense that we are on the brink of civil war,” Mr. Lévy says. “The worst part is that the country’s two main political forces now have an interest in the riots—Le Pen because she would take power, Mélenchon because he would take control of the streets. This domestic Yalta is the nightmare of all moderates, whether conservative or liberal.”Marine Le Pen is the leader of the National Rally party, and Jean-Luc Mélenchon of La France Insoumise, or France Unbowed.

Mr. Lévy characterizes them as “far right” and “far left,” respectively, which is also how most mainstream media label them. Unlike the media, however, which reserves the word for Ms. Le Pen, he calls them both “fascists.”Given the collapse of the French political center, it is possible that these two extremes will face off against each other in a presidential election next May, the rest of a crowded field having been eliminated in April’s first round of voting.

Mr. Lévy is both adamantly liberal and a staunch defender of Western Judeo-Christian values. What does he think of the prospect of a presidential runoff between Ms. Le Pen and Mr. Mélenchon? He resists entertaining the premise, telling me that I’ve fallen into the “habit of French journalists,” who “act as though the outcome were already decided, as though it were a foregone conclusion, six months in advance, that the final battle will be fought between the two extreme forces, the two new forms of fascism. Well, I don’t believe it.”

Mr. Lévy says he is a political “optimist” and has “a different hypothesis”: that “the French people are not as wretched as they are made out to be.”He is convinced that “in the final months, a third possibility will emerge. Perhaps it will be someone already in the race; perhaps it will be someone no one saw coming.”Either way, “this person will break the deadly deadlock between the two rival fascists and bring France back into the fold of democratic normality.”Finally he says that in the event of a Le Pen-Mélenchon runoff, “I will never force myself to choose between them. I will never cast a vote for either of them.”

Mr. Lévy is a longstanding defender of Israel. “From the point of view of Judaism alone,” he says, “Mélenchon is an unapologetic antisemite who makes the kind of remarks one hears from Tucker Carlson or Nick Fuentes in America—and does so without the slightest embarrassment.”

Ms. Le Pen’s party, “which had once declared itself purged of its former antisemitism,” now sees the problem resurface in press reports that party president Jordan Bardella wrote antisemitic text messages as a teenager in the 2010s. “Bardella could, of course, simply have said that he had made a youthful mistake,” Mr. Lévy says. “But no. There is something in his denial, in his insistence that it never happened, in his childish fury toward the newspaper that investigated his antisemitic past, that sounds like an admission.”

Mr. Lévy regards Ms. Le Pen and Mr. Mélenchon with equal distaste. “They are a right-wing and a left-wing version of the same populism—a right-wing Trumpism, if you like, and a kind of left-wing Trumpism, both sharing the same fundamental tendencies.”Among those tendencies: “indulgence toward [Vladimir] Putin, betrayal of [Volodymyr] Zelensky, nationalist and isolationist retrenchment, and a refusal to take any further steps toward Europe. Also, an economic policy that will leave France among the nations heading to bankruptcy.”It is a death match, he says, over “which of them will have the dreadful privilege of ruining this country.”

Mr. Lévy sees France in the midst of a “double tectonic shift, to the right and to the left. Both paths lead to French disaster. They are the two jaws of the vise in which I refuse to let my country be trapped.”The same, he says, is true of the U.S. “You too have two extremes joining hands: MAGA and the new Democrats who make anti-Zionism—that is, antisemitism—the alpha and omega of their politics. You know very well that this face-off would be fatal to American democracy. Well, exactly the same is true of France.”

The threat is “no longer even a political danger,” he adds. “It is a metapolitical one. It is the destruction of the social bond itself.”That entails “rage and fury, devoid of hope, of any vision of the future, with the sole aim of shattering the social contract itself.”To prevent this, he says, we must “block the arsonists on both sides at a distance: those who set fire to people’s souls, the incendiaries of the mind.”

Shouldn’t Emmuanel Macron, the president since 2017, take some blame for leading his country to this pass? Mr. Lévy pushes back. He says the portrayal of Mr. Macron “in diabolical terms by both right and left is, as far as I’m concerned, terribly unfair.”Mr. Lévy has been intensely critical of Mr. Macron for the “unilateral recognition of the state of Palestine, which gifts a political victory to Hamas and rewards the worst terrorism.”But there is “at least one area in which Macron has been impeccable: his support for Ukraine. Even today, when the United States seems to be siding with Russia, thank goodness Macron is there to keep alive the bond that ties Ukraine to its European home. At least for this, he should be praised.”

Our conversation occurs the same day that Steve Witkoff, Mr. Trump’s special envoy, calls Mr. Putin “a humanitarian.”“It’s properly disgusting,” Mr. Lévy says, “an insult to the Ukrainian dead, an insult to the American creed, and an insult to all decent Republicans who have devoted their lives to fighting, first, the Soviet Union, and then its Putinist avatar, and fighting, more broadly, every form of authoritarianism.”

Mr. Lévy wasn’t initially hostile to the French protests. “The student movement was obviously sympathetic at the outset,” he says. “Its demands—more teachers, better conditions in our high schools—were entirely worthy of sympathy. But the whole thing has been completely hijacked by the far left of Mélenchon,” who took “the enormous risk of calling for violence, legitimizing it, and casting a kind of political curse on the forces of the republican police.”Mr. Mélenchon “is now Le Pen’s best campaign surrogate. . . . Mélenchon and, of course, the rioters, are doing all the work for her.”

Don’t expect it to stay in France: “My country seems to be on the front line of a phenomenon now spreading across Europe, and perhaps throughout the entire West: an explosion of nihilism.”By which he means “a social movement that seeks not to bring about one kind of society or another but, instead, no society at all.”The violent protests are “not directed against this or that injustice, but against the very idea of justice—a revolt not against this or that government, but against the very idea of an organized society.”

Mr. Lévy insists that these “cold riots have nothing in common with May 1968,” when he joined the protest movement as a young adult. “There is a whole part of the book devoted to the events of ’68 and the years that followed,” he says. “There was a climate of revolt then, of course, but with hope at the end of it.”When the students of that era “looked beyond France’s borders, it was not to repeat, like donkeys, ‘Gaza, Gaza, Gaza,’ but to protest against all the dictatorships then raging around the world.”

Vietnam was “a kind of shibboleth, he says, “but no one was fixated on it. It was one cause among many others. The protestors of the time were just as concerned with the victims of Soviet dictatorship in the U.S.S.R. as with the dictatorships in Latin America.”

The ubiquitousness of anti-Israeli symbols at the riots appalls Mr. Lévy. “Palestine flags—it’s terrible, but it’s true. Just as in New York, where ‘Globalize the intifada’ has become a password for a new generation of so-called progressives, the Palestinian flag is becoming a shibboleth for the most brainless of our rioters. This is where we are, in a sad remake of the international commitments of the past and, in fact, the explosion of a genuine left-wing antisemitism.”He says it is “a new phenomenon—in its scale, its nature, and its nihilistic and desperate character. And the fact is, no politician seems ready to confront it.”

Many politicians have embraced or stoked it. Apart from Mr. Mélenchon, Mr. Lévy cites Mayor Zohran Mamdani among the culpable.

“For me, Mamdani sitting in City Hall as the mayor is a stain on the spirit of New York,” he says. “This is shameful in a country that was conceived by the Founding Fathers as the new Jerusalem, and which was regarded by the Jews themselves as a second fatherland. This deterioration is difficult to imagine.”

What struck Mr. Lévy about Mr. Mamdani during last year’s campaign is that “antisemitism was not just a footnote in his rhetoric or his program. It was a driving force of his argumentation, the argument which made him even more popular.”Mr. Lévy is as proud a Jew as he is a Frenchman. Do Jews have a future in France? It has been reported credibly that Jewish businesses were especially targeted in the recent French riots.

“This is one of the main themes of my book,” he answers. “Jews have played a major part in making France what it is. If anyone should have to leave, it is not the Jews, it is the antisemites. I will make that case and fight for it with all my strength, to my dying breath.”Mr. Varadarajan, a Journal contributor, is a fellow at the American Enterprise Institute and at NYU Law School’s Classical Liberal Institute.