I've written this summary mainly for myself, but if it persuades you to read the book, then good.
Berman's thesis is that Islamism is the latest in a line of violent and totalitarian rejections of liberalism and should be seen and confronted in the same way as the extreme Left and Right were in the 20th Century. He rejects Tariq Ramadan's claim that Islam (and, by extension, Islamism) occupies a different "universe of reference", a different civilisation and culture, one that cannot be understood from a Western viewpoint. On the contrary, Berman shows how much even a fountainhead of Islamist ideology like Sayyid Qutb draws on Western ideas and categories and how the movement that he inspires conforms to type. He also looks at Western reactions to the totalitarian challenge, in the Thirties and since.
Berman starts with Camus's analysis of romanticism in The Rebel. Starting with de Sade, the radical impulse has tended towards the ultimate transgression or rebellion of death, either of others or of the self. What for de Sade and Baudelaire was a literary pose became for revolutionary groups an essential weapon: political assassination, the elimination of a figure of authority that would bring down the pillars of that authority. Precise targets became random ones, and, in the early years of the 20th Century, transformed into mass movements, which, to achieve their aims, sought mass death. This was one of the many elements that were shared by all these movements, whether of the Left or the Right. Mass death as a means to an end - the war to end all wars and to usher in the final state. The final doctrine, the final movement, the final state. Nihilism.
Berman's most enlightening chapters are the two that outline the ideas of Sayyid Qutb, the Egyptian idealogue of the Muslim Brotherhood. Islam as totality - there is no God but Allah and all derives from that single source: nature, man and all that man creates. Authority, therefore, can come only from God. Because it meant "the abolition of man-made laws" and a structure built on the only true law, Islam is "a universal declaration of the freedom of man from servitude to other men and from servitude to their own desires".
The West, on the contrary, is characterised by schizofrenia, a fatal division introduced by Christianity in its first centuries: the division between Greek rationality and Judaic piety - between the secular and the spiritual - ulitmately realised in the separation of politics and religion as practiced in liberal societies today. This is anathema - the enemy without that has infected the societies of the Umma.
Like the radical movements of the 20th Century, Qutb sees Islam as threatened with annihilation from without (by crusading Christians and Zionists and their schizofrenic worldview) and threatened from within (by reformers such as Ataturk and all those who do not follow the word of God). The true Muslim must fight a defensive war (a jihad) against both enemies, a war that would be terrible and involve death in all the World, but the jihadis would prevail and the perfect society would be born of the victory.
Berman traces this message from Nasser's prison to Saudi Arabia and to Iran, from Afghanistan to Jersey City, from which the political exile, Sheikh Rahman, issued orders to kill tourists and Jews. The constraints that Qutb had applied to jihadis, such as avoiding the murder of women and children, were quickly forgotten, though the rest was not.
He turns to us (we are interesting), to how we react to anti-liberal threats. And tells one of those stories that become a filter which you apply to the news and to the world from that moment onwards. The story of the French socialists of the 1930s. The French Socialists were a successful party in the France of the 30s, and their leader, Léon Blum, was Prime Minister 3 times. Faced with the rise of the Nazis, Blum called for re-militarisation and opposition to Hitler. But a large faction in his party were of a different view. Fearing another war (another verdun) above all things, they sought to rationalise the hatreds and hysteria of Nazi Germany. They tried and succeeding in seeing something in Nazi complaints, in Nazi conspiracy theories. And they turned on those within their own society who would fight back - they were the real enemies. The real dangers to peace were the warmongers, the arms manufacturers, the international financiers, some of whom were Jewish (as was Blum). Come the invasion, and the proposal of Marshall Petain to create a pro-Nazi government, the majority of the Socialists voted in favour. Some ended up in the Vichy regime, passed the anti-Jewish laws and sent the police to round up Jews so that they could be sent to the concentration camps.
Berman explains their evolution with reference to their irrational faith in the idea of a rational world. If people behave so irrationally, mustn't there be a rational explanation? As rational beings, are we not duty-bound to understand their irrationality before condemning them? Surely, there are powerful, explicable forces at work and if we understand those forces, then we can deal with them. He illustrates this with another admonitory tale. That of the reaction to the 2nd Intifada in 2002.
A wave of suicide bombings hits Israel. The Israelis react. Protests across the world. A mass anti-globalisation march in Washington raises the chant of "Martyrs, not murderers". At the annual Socialist Scholars Conference (at which Berman has spoken several times), an Egyptian speaker who defends a suicide bomber is applauded. A delegation of the International Parliament of Writers visits the Palestinian territories. Breyten Breytenbach claims the Jews see themselves as a Herrenvolk (ie Aparthied whites, a Nazi Master Race). According to Jose Saramago, the Israelis' hounding of Arafat in his Ramallah compound was "a crime comparable to Auschwitz". Berman quotes from Saramago's El Pais article which depicts Israel as a "blond" David firing missiles from helicopters at innocents and, concerning suicide bombers, concludes, "Israel still has a lot to learn if it is not capable of understanding the reasons that can bring a human being to turn himself into a bomb".
What is most interesting, however, is the reaction of the self-righteous after the Israelis have managed to suppress the suicide attacks. All the Palestinian achievements of the 90s have been destroyed - the economy, which had put forth buds, is virtually non-existant; poverty is now rife; hope of any sort of normal life completely illusory. But the suicide bombings have peaked and faded. Yet despite the real suffering that the Palestinians must now endure, world protests fade as well. As if we have returned to normality. The bombings had brought out the rationalisers among us; with the pause in the bombings came a silence from the rationalisers.
There is a lot more, but that is what I have kept with me from the book.