The eminent historian and public intellectual Niall Ferguson looked at what happened in Paris and somehow saw Rome. In his column for The Sunday Times of London, he conjured up Edward Gibbon, who wrote of the decline and fall of the Roman Empire. Gibbon said Rome fell to barbarians who “extended the promiscuous massacre to the feeble, the innocent and the helpless” — pretty much, Ferguson says, what “we witnessed in Paris on Friday night.”

Ferguson is the author of many books on economics and history, and is affiliated with all the usual prestigious institutions (Harvard, Stanford, etc.). In addition, he has been anointed by Henry Kissinger as his chosen biographer. We are not talking Donald Trump here.

Yet Ferguson’s language in his column approaches Trump’s. Ferguson castigates Europe for being weak and spineless. “It has grown decadent in its shopping malls and sports stadiums,” he wrote. “At the same time, it has opened its gates to outsiders who have coveted its wealth without renouncing their ancestral faith.” Heinrich Heine, an ex-Jew, once wrote that conversion to Christianity was “the ticket of admission to European culture.” Is it now necessary to get into a mall?

To be sure, Ferguson makes the obligatory bow to tolerance. “It is doubtless true to say that the overwhelming majority of Muslims in Europe are not violent,” he says. But his words give intellectual heft to what is suddenly an explosion of anti-Muslim sentiment in both Europe and the United States. In America, Republicans have exploited the Paris massacres to warn about a wave of Syrian refugees heading our way, their numbers inflated by Trump from an anticipated 10,000 to 250,000. Whatever the number, Jeb Bush would give priority to Syrian Christians.

The governors of several states vow they will accept no more Syrian refugees. Predictably, some GOP candidates have raised the possibility of terrorists slipping into refugee stream. They inadvertently echo the American politicians of the 1930s and 1940s who wanted to keep refugees from Nazi Germany out of this country, asserting that there were communists among them.

I would have to be willfully ignorant to overlook that much terrorism — including, of course, the mass murders of Sept. 11, 2001 — has been carried out by Muslims, usually Arabs. And I am not one to deny that cultural differences matter and can matter greatly. But the Europe that Ferguson fears will go the way of Rome has shown in the recent — and not so recent — past that its Christians can act plenty bestially on their own.

In the name of one true Christianity or another, Catholics slaughtered Protestants and Protestants slaughtered Catholics, with an energy and a ferocity that are impossible for us now to appreciate. Jews were always a tempting target. A pious Czarist Russia countenanced 660 pogroms in 1905 alone — a statistic gleaned from Ferguson’s own book, “The War of the World.”

Nazi Germany’s Catholic and Protestant clergy were largely mute as the nation’s Protestant and Catholic soldiers murdered with abandon. “Protestants welcomed the Nazis’ ‘national revolution’ with an enthusiasm and hope for spiritual revival comparable only to the fervor with which they had endorsed war in 1914,” writes Nicholas Stargardt in his new book, “The German War: A Nation Under Arms, 1939-1945.”

Last month, Hindus in India murdered a Muslim man for allegedly killing a sacred cow. The placid Japanese of today were yesterday’s rapists and murderers of Nanking and performed hideous medical experiments on prisoners of war. Stalin, a former seminarian, killed millions; Mao did the same. Buddhists, Hindus, Christians, Jews — you name it — have at times been the barbarians Ferguson alludes to. As recently as 1995, Serbian Christians massacred about 8,000 Muslim men and boys at Srebrenica, Bosnia.

There is danger in naivete. A threat exists. Paris has been grievously wounded; Beirut and Ankara, too. The Islamic State claimed the downing of a Russian passenger plane and, in the Middle East itself, a state has arisen that has made beheading, sexual slavery and religious hatred a matter of policy. It is Muslim, it’s true, but Nazi Germany wasn’t.

Among the values Ferguson surely wants to protect is tolerance — religious, of course, but ideological, sexual, racial and anything else you can think of. It is at the core of Western culture and why his wife, Ayaan Hirsi Ali, fled Somalia for the West — first Europe and now the United States. We all have the same enemy. It is not Islam. It is intolerance.

Richard Cohen is a columnist for The Washington Post. His email address is: cohenr@washpost.com.