Sheer luck saved large numbers of people from being killed or wounded late last week in attempted car bombings in central London and Glasgow Airport. Yet even though British authorities had fortune on their side, their rapid and coordinated response still offers an example of how a liberal democracy can work to prevent and punish terrorism — without operating outside the law or sacrificing individual liberties. In the two years since bombs exploded in London’s transit system, Britain has kept close watch on extremists, extradited those who are wanted for crimes committed in other countries, and explored the affiliations of individuals involved in terrorist plots.

There are worthwhile lessons to be learned from the British effort. In their effort to deal with terrorism, authorities can work within the law. They do not require unconstrained power. The threat from suicidal fanatics is to be countered by means of sound intelligence, conventional police work, legal adaptations that do not create a law-free zone, and leadership that distinguishes law-abiding communities from the crazed Islamist ideologues. Britain is fighting terrorists without branding them unlawful enemy combatants, without torturing them, and without frightening the populace with evocations of an apocalyptic war between good and evil.