How do you prevent a terror attack?

„So next time the Norwegians will arm more of their police. And next time, authorities will investigate the ranting manifestos of any anti-Muslim extremist who claims to lead a revival of the medieval Knights Templar. But Friday’s attack in Oslo by Anders Behring Breivik teaches some broader lessons, too: There are homicidal cults all over the world — some in Muslim countries and some in the heart of Europe. Some attackers will be found insane by courts, but others will have a diabolical logic and lucidity — and the world has to be ready for all of them.

Most important, the next time the weapons of choice may not be a bomb and a semiautomatic rifle, as in the case of the Oslo attacker who killed 76 people. Lunatics and sane plotters alike may have access to chemical and biological weapons that could kill thousands. As in so many terrorist cases — and with al-Qaeda itself — this latest extremist didn’t sneak up on the world. He all but announced his anti-immigrant views on the Internet.

To understand the dangers posed by these borderline extremists, I recommend a new report by Richard Danzig and his colleagues at the Center for a New American Security. It’s a case study of the only terrorist group that has successfully used chemical and biological weapons on a mass scale — the Japanese religious cult Aum Shinrikyo. It poisoned the Tokyo subway system with sarin, a deadly nerve gas, in 1995, causing 13 deaths and an astounding 6,252 injuries.

Danzig’s report, drawn from interviews over the past three years with imprisoned members of the cult, is revelatory. It shows how extremists are driven toward ever-more toxic weapons. And it illustrates how lax police can be until disaster happens. Though the Japanese police had evidence that Aum Shinrikyo was producing chemical weapons, they couldn’t prosecute because no Japanese law specifically banned the manufacture of poison gas!”