After the September 11 attacks, Americans who had never given any thought to the psychology of Islamic terrorism could not help asking what had driven the Al Qaeda hijackers to such an extreme of evil. “Why do they hate us?” was the question of the hour, and two possible answers quickly emerged. According to one argument, most popular on the left, Islamic terrorism was a natural response to specific political grievances: the Israeli-Palestinian conflict, Western exploitation of Middle Eastern oil, American support for Arab despots. Al Qaeda, on this view, was a resistance movement like the IRA or the PKK, and could be pacified by strategic concessions.The right, on the other hand, was more inclined to the view articulated by President Bush, that “they hate us because we are free.” If that were the case, negotiation and compromise with Al Qaeda would be pointless because nothing short of a capitulation of our fundamental values could appease the enemy.

The first interpretation is more appealing, and not just because it appears more sophisticated. It invokes a democratic society’s deepest beliefs about human nature: that human beings are fundamentally rational, that we all want peace rather than war,and that we respond to tangible incentives. But the more we learn about Islamic radicalism, the clearer it becomes that the second, seemingly simplistic explanation, is actually the correct one. This is not to say the many injustices in the Arab world do not exist, or that they do not contribute to the recruitment of terrorists. But for the jihadists themselves, as Mary Habeck shows in her important and necessary new book, “Knowing the Enemy: Jihadist Ideology and the War on Terror” (Yale University Press, 256 pages, $25), hatred of the United States is more than a political tactic; it is a religious and ideological principle from which they will never be dissuaded.

In fact, the current American debate over why Al Qaeda hates us is very much like the Western debate in the 1930s about the motives of Hitler. Then, too, there was a party arguing that if only the causes of the Nazis’ grievances could be removed – the Treaty of Versailles, the Sudeten Germans, the Danzig Corridor – they would be satisfied. Today, such people are remembered as appeasers, and historical honor is given to those, like Churchill, who recognized that there are some enemies to whom compromise is only a sign of weakness.

The premise of Ms. Habeck’s study sounds simple enough, but it demonstrates an insight and forthrightness rare among Western pundits. Ms. Habeck, a professor at Johns Hopkins’s School of Advanced International Studies, believes that today’s Islamic terrorists – whom she insists on calling “jihadis,” in recognition of the central role of violence in their worldview – ought to be taken at their word. To interpret their religious beliefs as merely an expression of class, race, or regional grievance, she argues, is not only condescending but unwise. Just as there were once people who believed wholeheartedly in the real existence of fictions like “the master race,” so there are people today who sincerely believe that history is driven solely by the eternal struggle between Islam and infidelity.”To see why jihadis declared war on the United States and tried to kill as many Americans as possible,” Ms. Habeck writes, “we must be willing to listen to their own explanations.”

As Ms. Habeck shows, the jihadists make no more of a secret of their plans and beliefs than Hitler did when he wrote “Mein Kampf.” The method of “Knowing the Enemy,” then, is simply to read what the jihadists write – to scrutinze their treatises and pamphlets, speeches and Web sites. Ms. Habeck focuses particularly on the three most influential 20th-century theorists of Islamic terror: Hassan al-Banna, the Egyptian founder of the Muslim Brotherhood; Sayyid Abul A’la Mawdudi, the Pakistani founder of the extremist party Jama’ati-i-Islami; and Sayyid Qutb, a Brotherhood member whose visit to America in the late 1940s inspired his fanatical hatred of modernity and the West.

Between them, these men and their followers developed a theory of Islam that deserves to be called totalitarian, though Ms. Habeck uses the term only sparingly. Their central belief, from which so many evil consequences flow, is that Islam is not just the only true, but the only permissible religion. Everything that opposes its universal spread is evil and must be crushed. As Ms. Habeck writes, “They must, therefore, defeat a stunning array of enemies: the West, the Jews, the Christians, the Hindus, the ‘agent rulers’ [i.e., Arab governments they see as illegitimate], and any Muslims who do not agree with their form of Islam – the so-called apostates, heretics, and hypocrites.”

The last point is perhaps the clearest evidence of the jihadists’ totalitarian ambition. They are not just fighting on behalf of Muslims against the West, but on behalf of their own ideological vision of Islam against those whom they consider false Muslims. Ms. Habeck points to the importance, in jihadist tracts, of the notion of jahiliyya, or ignorance.Traditionally, the term is used to describe the benighted state of the Arabs before the advent of Muhammad. Sayyid Qutb argued, however, that even Muslim countries not governed by his puritanical version of Shariah are themselves in “ignorance.” “By using this term,” Ms. Habeck explains, “Qutb was in essence declaring that all Muslims not following Islamic law were unbelievers who could be fought and killed.” This helps to explain why Sunni terrorists in Iraq are even more intent on murdering Shiites than Americans, and why Osama bin Laden hates the Saudi royal family as much as the United States.

“Knowing the Enemy” reminds us that Al Qaeda is not like an ordinary political party, or even like an ordinary terrorist cell. Totalitarian movements like Nazism and Communism, as Hannah Arendt argued in “The Origins of Totalitarianism,” are called movements for a reason: They demand constant motion. They can never be content with any political settlement because they have no interest in equilibrium. Their power and danger comes from their love of permanent struggle, motivated and confirmed by an ideology that sees the world as a constantly replenished source of enemies.

So too with the jihadists: “In their reading of history,” Ms. Habeck writes, “the conflict between the United States and Islam is part of a universal struggle between good and evil, truth and falsehood, belief and infidelity, that began with the first human beings and will continue until the end of time.” Such an enemy can be fought more or less intelligently, more or less honorably; but that it must be fought, Ms. Habeck leaves no doubt.

akirsch@nysun.com