By THE WASHINGTON TIMES

President Obama’s top counterterrorism adviser knows very little about terrorism, and that’s scary for America.

John Brennan, deputy national security adviser for counterterrorism and homeland security, asserted in a speech last month that the United States cannot be at war with terrorism because terrorism is only a “tactic.” Terrorism, however, is also a strategy and method, with a long history and extensive theoretical literature. This is why it is an “-ism” and not simply “terror.” It is bewildering that Mr. Brennan would make such a glaring error on such a fundamental concept.

Mr. Brennan also asserted that “violent extremists” are victims of “political, economic and social forces.” This dense statement implies that counterterrorism should focus not on terrorists themselves but the underlying causes that purportedly “victimized” them. It’s similar to the discredited argument that the way to fight urban crime is through big-government social programs rather than putting more police on the beat. Making terrorists into victims also legitimates their grievances, which is a strange way to fight them.

Mr. Brennan’s curious views may be part of a larger move by the O Force to redefine terrorism. According to Michele Flournoy, undersecretary of defense for policy, an effort is under way to revise counterterrorism strategy. Last week, at a speech at the Center for a New American Security, she said, “one of the discussions we’re having in that context is what are the root causes of extremism.”

The anguished quest for the “root causes” of political violence is hardly new. The root cause of terrorism has been the holy grail of counterterrorism research for decades. Most scholars have ruled out the simplistic notion that terrorism is the product of vague social or economic forces or that terrorism arises from backwardness or privation. Were that the case, there would be a great deal more terrorism in the world, and it would not be the hobby of a billionaire’s son like Osama bin Laden. So a strategy that focuses on mitigating supposed root causes is hamstrung by the fact that the causes cannot reasonably be determined and that the United States is incapable of solving the world’s social and economic problems.

Mr. Brennan also has been waging his own crusade on jihad. He claims “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.” It’s true that the term jihad can refer to the inner struggle for purification, something known as the “greater jihad” in Islamic theology. But jihad also can mean the violent struggle against non-Muslims for the defense or extension of the Islamic faith, something known as the “lesser jihad,” which to the United States is the greater threat. Mr. Brennan chooses to blind himself to this definition of the word, which is like not understanding that the word “prey” can be both a noun and a verb, each with very different implications.

Mr. Brennan believes attacks on the United States should not be justified in religious terms, but this is how terrorists in fact do justify them. His obtuseness is dangerous. Knowing the enemy is a necessary precondition for victory. A good starting point is bin Laden’s November 2002 “Letter to the American People” in which he explicitly addresses the question of why al Qaeda is at war with the United States. It is a comprehensive critique of American society, which he describes as the “worst civilization in the history of the world.” Bin Laden’s missive is steeped in religious language and is the product of a radical Islamic intellectual tradition that goes back more than a century.

Mr. Brennan’s view of Islam as a universally benign force may lead him to dismiss some of al Qaeda’s justifications for violence, which reveals willful ignorance. He may maintain that he knows more about Islam than our enemies, but they are dying to prove him wrong.