Google "Islamist" and you'll get more than 24 million hits. Google "jihadist" and you'll get millions more. Yet I bet the average American could not tell you what it is that Islamists and jihadists believe. And those at the highest levels of the U.S. government refuse to do so.

Why? John Brennan, the top counterterrorism adviser in the White House, argues that it is "counterproductive" to describe America's "enemy as 'jihadists' or 'Islamists' because jihad is a holy struggle, a legitimate tenet of Islam, meaning to purify oneself or one's community, and there is nothing holy or legitimate or Islamic about murdering innocent men, women and children." To describe terrorists using "religious terms," he adds, would "play into the false perception" that the "murderers" waging unconventional war against the West are doing so in the name of a "holy cause."

I get it. I understand why it would be useful to convince as many of the world's more than a billion Muslims as possible that Americans are only attempting to defend themselves against "violent extremists." By now, however, it should be obvious that this spin — one can hardly call it analysis — has spun out. The unpleasant fact is that there is an ideology called Islamism and, as Yale professor Charles Hill recently noted, it "has been on the rise for generations."

So we need to understand it. We need to understand how Islamism has unfolded from Islam, and how it differs from traditional Islam as practiced in places as far-flung and diverse as Kuala Lumpur, Erbil, and Timbuktu. This is what Bassam Tibi attempts in his most recent book, published this year, Islamism and Islam. It has received nowhere near the attention it deserves.

A Koret Foundation Senior Fellow at Stanford University, Tibi describes himself as an "Arab-Muslim pro-democracy theorist and practitioner." Raised in Damascus, he has "studied Islam and its civilization for four decades, working in the Middle East, South and Southeast Asia, and Africa." His research has led him to this simple and stark conclusion: "Islamism is a totalitarian ideology." And just as there cannot be "democratic totalitarianism," so there cannot be "democratic Islamism."

Brennan and other American and European officials are wrong, Tibi says, to fear that "fighting Islamism is tantamount to declaring all of Islam a violent enemy." As for the Obama administration's insistence that "the enemy is specifically, and only, al-Qaeda," that, Tibi writes, "is far too reductive."

Tibi also faults Noah Feldman, the young scholar who advised the Bush administration, and who insisted, despite abundant evidence to the contrary, that sharia, Islamic law, can be viewed as "Islamic constitutionalism." Feldman failed to grasp the significance of the "Islamist claim to supremacy (siyadat al-Islam)," the conviction that Christians, Jews, Hindus, and Buddhists are inferior and that their inferiority should be reflected under the law and by government institutions.

Tibi makes this important distinction: All jihadists are Islamists, but not all Islamists are jihadists. In other words, not all Islamists are committed to violence, including terrorism, as the preferred means to achieve their goals. He asks: "Can we trust Islamists who forgo violence to participate in good faith within a pluralistic, democratic system?" He answers: "I believe we cannot."

Chief among Islamist goals, Tibi writes, is al-hall al Islami, "the Islamic solution, a kind of magic answer for all of the problems — global and local, socio-economic or value-related — in the crisis-ridden world of Islam." Islamists ignore the fact that such governance has been implemented, for example, in Iran for over more than 30 years, in Afghanistan under the Taliban, in Gaza under Hamas, and in Sudan. It has never delivered development, freedom, human rights, or democracy. As for Turkey, Tibi sees it as "not yet an Islamist state" but heading in that direction.

Tibi makes some arguments with which I'd quarrel. For example, he views Saudi religious/political doctrines as a "variety of Salafism (orthodox, traditional Islam) not Islamism." I would counter that Salafism is a variant of Islamism, albeit one based not on the writings of Hassan al-Banna, who founded the Muslim Brotherhood in 1928, but on nostalgia for the glory days of the seventh century.

Nevertheless, the debate Tibi is attempting to initiate is necessary — and long overdue. During the Cold War there was a field of study known as Sovietology. It was taught in our most elite universities with strong U.S. government support.

Why isn't Islamology — not Islamic theology, or "Muslim-Christian understanding," or "Islamic thought" — a discipline today? For one, Tibi observes, because to "protect themselves against criticism, Islamists have invented the formula of 'Islamophobia' to defame their critics." (How did Stalin not come up with Sovietophobia or Russophobia?) And of course if such slander fails to intimidate, there are other ways to shut people up: Tibi has "survived attempts on my life by jihadists."

A second reason for the absence of Islamology: The U.S. government cannot back the study of an ideology it stubbornly insists does not exist. Finally, those who do fund anything to do with Islam on campus — for example, the Gulf petro-princes who have given tens of millions of dollars to Georgetown and Harvard — have a different agenda, one that does not include free and serious inquiry. We ignore what they are doing — and what Tibi is telling us — at great peril.