WASHINGTON - A gunman named Muhammad has terrorized the Washington area for weeks. He was a follower of Louis Farrakhan and joined the security detail at the Million Man March in Washington in 1996. He had expressed admiration for the 9/11 terrorists and violent hatred for the infidel United States. So: Could this murderous rampage have anything to do with, um, Islamic terror? If you have been watching television you already know the answer: Naaaah.

Sometimes it seems that the single most important prerequisite for a successful media career is a talent for ignoring the obvious. Every interviewer on television congratulates himself or herself on "asking the tough questions." But the questions that most urgently need to be answered are the easy questions: Who are John Muhammad and John Malvo? What was their relationship? What was their background? The police have been very quick to reassure the public that John Muhammad did not take orders from al-Qaeda. Unlike the shoe bomber, Richard Reid, and the dirty-nuke bomber, Jose Padilla, Muhammad seems to have been acting for motives and purposes of his own: his own disappointments and resentments, his own greed and rage, and quite possibly his own weird personal dynamic with his "stepson." In other words, Muhammad was not a Muslim who became a killer. He was a killer who became a Muslim.

This reassurance, however, is no reassurance at all. It raises what may be the single most important issue in the next phase of the war on terror: Is radical Islam becoming what black nationalism and communism and fascism each were in their day--the ideology of choice for psychopaths with a murderous grievance against the world?

Disturbed personalities can be found in every society and in every culture. In the West, they tend to be drawn to the animal-rights movement, to anti-globalization, and to radical environmentalism. But none of these movements looks very much like a threat to the existing order of society, especially not compared to al-Qaeda or Hezbollah. No wonder that at this April's big anti-globalization march in Washington, the anti-Nike protesters wore Palestinian keffiyehs. No wonder that the star attraction at the anti-Iraq-war march in Madrid last month were two young European women dressed in suicide-bomber bikinis. There was an undercurrent of effeteness and silliness about the protests of the 1990s--all those ridiculous papier mache puppets! Compared to that, from the point of view of the radically alienated, radical Islam is the real thing.

So what can we do to protect ourselves?

One lesson taught by the snipers is the comparative futility of what we now call "homeland security": measures to improve the defence of aircraft, refineries, nuclear reactors and other potential targets. Homeland security protects things--and terrorists target people.

Better to continue to demand better police and intelligence work. The Patriot Act of 2001 gave the FBI, at long last, authority to send agents to listen to the sermons preached in mosques and to read the postings on extremist Web sites--and that will help. Ultimately, though, the police depend for their information on the help of alert citizens. It was good detective work that identified John Muhammad and John Malvo as the killers--it was a tip from a motorist that actually turned them in.

And this is the supreme lesson of the sniper case: It is the North American Muslim community that must be the first line of defence against Islamic terror.

In September, Assistant Attorney General Larry Thompson thanked the Muslim community of western New York for turning in six Buffalo men of Yemeni origin who had undergone training at al-Qaeda camps in Afghanistan and who were allegedly plotting terrorist attacks inside the United States. This patriotic act apparently split the area's Yemeni immigrant community. The imam of the mosque accused the police of harassment, and passed the hat around his not-very-affluent membership to raise $700,000 bail. The Pakistani newspaper, The Dawn, quoted one unnamed mosque member's excuse for the arrested men: "These men were looking for adventure and thought it was exciting to visit an al-Qaeda camp and listen to their leaders. They never wanted to commit an act of terrorism. They love America." Uh-huh.

It's been rightly said that the war on terror is not a war between the West and Islam--it is a civil war within Islam about the future of the Islamic world. The writer Christopher Hitchens has termed Islamic extremists "Islamo-fascists" and that term is taxonomically exact. Just as European fascism sought to beat back democracy and liberty in the 20th century by invoking a medieval past that never was, so now do the Islamic fascists of al-Qaeda and Hezbollah and their many sympathizers invoke the myths of ancient Arabia against democratization and westernizatoin in the 21st.

The Muslim communities of the West are one of the most decisive theatres of this civil war. And the case of John Muhammad reminds us that in this theatre, our victory is far from won. 

David Frum is a visiting fellow at AEI.