As a non-Jewish historian of France with several dear Jewish friends in that country, I read with great dismay the recent news articles suggesting that many French Jews are considering emigrating to Israel to escape the rising tide of anti-Semitism most recently demonstrated in the brutal attack in a Paris kosher market that left four Jewish patrons dead on the eve of the Jewish Shabbat last week.

Of course, Jews in any country have a perfect right to make aliyah to Israel any time they choose to do so, and, as Prime Minister Netanyahu declared last week, they will be welcomed there with open arms. What causes the feeling of dismay and regret in this longtime student of French history is not Israel’s potential gain but France’s potential loss.

I think of the extraordinary contributions that Jews in France have made to the vibrant intellectual life of that country:  The list would include, among too many others to include here, the names of Raymond Aron, Julien Benda, Marc Bloch, Jacques Derrida, Emile Durkheim, Claude Levi-Strauss, Darius Milhaud, and Marcel Proust.

In addition to such path-breaking pioneers in philosophy, sociology, anthropology, history, and literary criticism, hundreds of thousands of ordinary French Jews have played a productive and integral role in their country’s social and political life.  As France’s Prime Minister Manuel Valls (who was born in Spain to a Spanish-Catalan father) has put it so bluntly: “If 100,000 French people of Spanish origin were to leave, I would never say that France is not France anymore. But if 100,000 Jews leave, France will no longer be France.”

The modern history of France’s relationship to its Jewish population is marked by high points and low points: In 1791 it was the first country in the world to grant civil equality to Jews. A low point came in the second half of the 1890s, when the unjust treason conviction and imprisonment of a Jewish army officer, Captain Alfred Dreyfus, for leaking military secrets to Germany precipitated a wave of anti-Semitism on the extreme right.

One of the observers of Dreyfus’s condemnation and of the cries of “Death to the Jews” that reverberated throughout the streets of Paris was the Austrian journalist Theodor Herzl. He subsequently founded the movement of political Zionism in part because the outburst of anti-Semitism during the Dreyfus Affair  in the most democratic, liberal, tolerant country in Europe persuaded him of the impossibility of assimilation and the necessity for a Jewish state to serve as a safe haven for threatened Jews everywhere.

A high point came when Dreyfus was eventually exonerated and reinstated as a major in the French army. The forces of liberal democracy, humanism, and tolerance triumphed over the forces of extreme nationalism, religious prejudice, and intolerance, which enabled most French Jews to feel secure in the secular French Republic.

Then the fall of France in 1940, the Nazi German occupation of the northern part of the country, and the advent of the collaborationist Vichy regime in the southern part ushered in another low point in the fortunes of Jews in France. Anti-Semitic laws enacted by the Vichy government severely restricted their rights. French authorities rounded up and deported some 76,000 Jews to the death camps of the Third Reich, of whom less than 2,500 survived.

In the decades since the dark days of 1940-1945, the Jewish community in France has thrived and prospered. Its 500,000 members represent the third largest Jewish community in the world (after Israel and the United States).  France has had five prime ministers of Jewish heritage, more than any other country save Israel.

The ever-present scourge of anti-Semitism was confined to the ideological extremes, from the right-wing Front National of Jean-Marie Le Pen to the proponents of Islamic terrorism such as that recently witnessed in Paris. (In recent years Le Pen’s daughter and political heir, Marine Le Pen, has replaced the anti-Semitism of her father with a virulent nativist rhetoric focusing on the threat to the French way of life posed by Islamic immigration from France’s former colonies in North Africa.).

Indeed, the principal source of anti-Semitism in France is no longer to be found in the old extreme right groups that had targeted Jews from the Dreyfus Affair to Vichy. It now emanates from the impoverished suburbs surrounding major French cities, where a small minority of unemployed, restless youth in immigrant families from North Africa and sub-Sahara Africa are attracted to the siren song of Al Qaeda and the Islamic State and are willing to commit terrorist acts to promote the cause.

More than 7,000 of France’s half a million Jewish citizens emigrated in 2014. Some predict that that number will double this year. Others forecast that half the population of French Jews will be gone by the end of the decade.

As the Jewish citizens of France contemplate the choice or emigration or the maintenance of their religious and/or cultural identity within France, the French government must leave no stone unturned in the process of protecting one of that country’s most precious resources. If it fails, to repeat the plaintive observation of Prime Minister Valls, France will no longer be France.

William R Keylor is Professor of International Relations and History in the Pardee School of Global Studies at Boston University. He is the author of several works on the history of modern France and French foreign relations, served as president of the Society for French Historical Studies, was a visiting professor at the Institut d’Etudes Politiques de Paris (Sciences Po), and was named Chevalier de l’Ordre National du Mérite by the French Republic.