Why do American diplomats sign their essays Anonymous whenever they have something large and upsetting to say? Why not Publius? It was Anonymous, anyway, who published a commentary on the Islamic State in the New York Review of Books of August 13—Anonymous, who is said, by the editors, to be “formerly an official of a NATO country,” which could mean Canada, of course, or Estonia. But the United States does seem probable. And Anonymous is said to be someone with “wide experience in the Middle East.” An expert, therefore, accustomed to the sobrieties of power. Anonymous, then—how does Anonymous account for the Islamic State? With what analysis? Anonymous is at a loss. Anonymous confesses to “bafflement.” This is large, and it is upsetting.We like to suppose that known patterns of behavior dominate the world, which means that, if a big revolutionary movement has arisen, the normal and predictable causes must surely be at work; and the bigger the movement, the more normal and predictable the causes. The Islamic State consists of tens of thousands of jihadis with oil revenues and a functioning bureaucracy and a hip media, ruling vast portions of Syria and Iraq, even apart from its noncontiguous provinces in Africa, which adds up to more than big. But the normal and predictable causes that account for revolutionary movements (national grievances, experience of national humiliation, economic suffering, peasant hatred for cities, proletarian hatred for aristocrats, charismatic leaders, etc.) seem insufficient to explain these developments, or entirely inapplicable. Nor can the movement’s successes be attributed to the well-established strategies of successful military insurgencies of the past, as memorialized by Mao Zedong and the grand theorists of guerrilla war. The Islamic State and its variously-named predecessor organizations in Iraq have sometimes behaved as if entirely unaware of the doctrines of guerrilla war, and have sustained major and unnecessary losses. But losses appear to do them no harm at all.A telling paragraph in Anonymous’s essay:Nor have there been any more satisfying explanations of what draws the 20,000 foreign fighters who have joined the movement. At first, the large number who came from Britain were blamed on the British government having made insufficient effort to assimilate immigrant communities; then France’s were blamed on the government pushing too hard for assimilation. But in truth, these new foreign fighters seemed to sprout from every conceivable political or economic system. They came from very poor countries (Yemen and Afghanistan) and from the wealthiest countries in the world (Norway and Qatar).More:Analysts who have argued that foreign fighters are created by social exclusion, poverty, or inequality should acknowledge that they emerge as much from the social democracies of Scandinavia as from monarchies (a thousand from Morocco), military states (Egypt), authoritarian democracies (Turkey), and liberal democracies (Canada). It didn’t seem to matter whether a government had freed thousands of Islamists (Iraq), or locked them up (Egypt), whether it refused to allow an Islamist party to win an election (Algeria) or allowed an Islamist party to be elected. Tunisia, which had the most successful transition from the Arab Spring to an elected Islamist government, nevertheless produced more foreign fighters than any other country.Maybe some points are, in fact, explicable. Anonymous discusses a number of new books about the movement, and one of those books, ISIS: Inside the Army of Terror, by Michael Weiss and Hassan Hassan, does a first-rate job of describing the Islamic State’s layers, at least in Syria and Iraq. The movement there enjoys an authentic following among Sunni Arabs in certain pockets, and the popular support conforms to a logic that we have seen among followers of other totalitarian movements over the last century—a popular support based on reasonable fears and practical calculations, admixed with a few intellectual confusions. The ordinary Sunnis in those pockets may dislike the Islamic State’s Quranic crucifixions, beheadings, lashings, and amputations, and may recoil at the mass slaughters. But the Sunnis have been terrified by the rise of Shiite power, and they see in the Islamic State a force that is willing to protect them. The Islamic State’s anti-crime policing goes down well, too. Weiss and Hassan quote a resident of the Syrian town of Deir Ezzor: “We never felt this safe for twenty years.” The Islamic State eagerly executes its own militants whenever they are accused of corrupt or criminal behavior, which counts as another grisly point in its favor, among the local Sunnis. The Islamic State sweeps the streets, protects the fisheries, controls the warlords, and regulates the economy. Oil revenues come its way because it understands the business. And it maneuvers cleverly among the tribes.Only, where does the Islamic State acquire the military strength, police capabilities, administrative efficiency, and economic sophistication to provide those several services? Here we seem to have returned to the realm of the inexplicable. The Islamic State enjoys the support of not a single powerful institution in other parts of the world. And yet, to judge from Weiss and Hassan’s account, these several strengths are not, in fact, mysterious. The Islamic State appears to have inherited the capabilities of the old Arab Baath Socialist Party of Saddam Hussein. Weiss and Hassan remind us that, back in 2003, when the American-led occupation forces settled into Iraq, the occupiers never did entirely take over the several towns that traditionally served as Baathism’s social base. A slice of Baathism’s security and military officer corps managed to survive. The slice launched an insurgency. The insurgency prospered. And it drifted in Islamist directions.Baathism’s Islamist drift may strike us as one more incomprehensible development, given the conventional wisdom among American journalists and regional scholars about Baathism and its “secular” outlook. Somebody ought to write a history of conventional wisdom, though. Baathism is an extremist movement that is also an adaptive movement, which means that over the decades the Baathists have known how to bask in the secular sun, in solidarity with their worldly comrades, the fascists and the communists, and have also known how to dip into the seas of Islam and breathe through their religious gills, in order to take their place among the other-worldy Islamists. And amphibiousness has been their genius. Saddam was Baathism’s greatest leader because he started out with an Islamic orientation and, even so, knew how to veer in communist directions during his years of glory; and he knew how to spin on his heels in the face of later difficulties and inscribe “Allahu Akbar” on his flag. And when he found himself under arrest and on trial in a Baghdad courtroom, he astonished the world by declaring Mussolini to be his role model.Here was a man with options. And it has been the same with Saddam’s military and security officers in the period after his defeat. The Baathist officers began by allying with the Sunni Islamist cause in occupied Iraq, their brothers in the anti-Crusader and anti-Zionist cause. And they ended by sailing the seas of sacred jihad, where they remain. Chief among their allies was Saddam’s vice president, Izzat Ibrahim al-Douri, a Sufi, who brought with him a Sufi Naqshbandi military faction of the Baath. (Conventional wisdom exclaims: “Not possible! Everyone knows that Sufis are peaceable!”) And so, the Islamic State acquired an officer corps. Also, administrative skills. Also, a security apparatus, whose sophistications you can read about in Weiss and Hassan’s pages. Which ought to catch our attention.America’s campaign against the Baath began, after all, with a land war in Iraq, under George H.W. Bush; which led to an intermittent air war under Bill Clinton; which led to a renewed land war under George W. Bush; which led to a renewed air war under Barack Obama, this time with the Baath having taken its place within the Islamic State. And signs of collapse have yet to appear. Naturally this makes for more than an American frustration. The Arab Baath Socialist Party in its two branches, Iraqi and Syrian, has turned out to be the worst affliction the Arab people has ever endured and a still worse affliction for the Kurds. It is true that, ever flexible, Baathism’s branches have diverged over the years (although, as I learn from Weiss and Hassan, al-Douri, the non-peaceable Sufi, tried to reunite them), even aside from the plunge into Islamism. But each new adaptation has proved to be expert at slaughter.Only, why do they slaughter people? The Islamic State in particular, with its Baatho-Islamist cadre—what is its motive? On this point, too, there is no mystery. The Islamic State has been eager to reveal its own thinking. The Islamic State slaughters for religious reasons—which is to say, for reasons that are bound to seem incomprehensible to us. It is piety that requires the efficiently organized jihadis to slaughter the poor unoffending Yazidi minority in Iraq; and to slaughter the Shia, which they have been doing for many years now, one suicide bombing after another; and to slaughter Christians; and would surely require them to slaughter the Jews, if only the Israeli Defense Force would do them the kindness of getting out of the way. Given the opportunity, the Islamic State would slaughter most of the world, if I understand the takfiri doctrine correctly. Slavery, too, is piety, in these people’s eyes. They pray before raping.And they have prospered! Their successes bear out political theory on a few points, but mostly they are a rebuke to political theory. They are the enemy and conqueror of every doctrine that has ever supposed human behavior to be predictable. This is the bafflement. Anonymous is right. They have scored a triumph over every theory of human progress that has ever been proposed. They are not the first people to score such a victory. We have needed their reminder, though. In recent decades we have liked to tell ourselves that, after the Nazis, mankind has learned its lesson. But mankind is not a lesson-learning entity. Civilizations can learn lessons. But civilizations come and go. Impassive mankind remains uninstructable and stupid, such that, if once upon a time the barbarities of the 7th century thrilled and inspired a substantial portion of mankind, we can be confident that 7th-century barbarities will remain forevermore a viable possibility.***To read more of Paul Berman’s analysis for Tablet magazine, click here.