The arrest last Tuesday of three suspects in a plot to carry out bombings in Germany offers crucial lessons about preventing terrorism. Some of those lessons have to do with the tactics of law-enforcement and intelligence agencies. But the most beneficial insight Americans could gain from the German example is that war is the wrong metaphor for a nation’s defence against terrorism. The investigation leading to this week’s arrests and the seizure of bomb-making material suggests that the terrorist threat is best countered not by armies on battlefield, but by meticulous police work, intelligence cooperation, and laws that strike a reasonable balance between civil liberties and the state’s obligation to protect the lives of citizens.

Germany’s interior minister is now calling for new laws that would permit preemptive detention of suspected militants and allow the government to plant surveillance software in the computers of persons suspected of ties to terrorist groups. In Germany as in the United States, it is for voters and lawmakers to thrash out the proper balance between privacy rights and security.

But this should be a debate about how best to cope with a particular type of criminal. It should not be inflated into a metaphor of endless war against an amorphous enemy.