A new Global Terrorism Index this week showed that terrorism went up from 2002 to 2007 – largely because of the conflicts in Afghanistan/Pakistan and Iraq — but has declined ever since. And the part of the world with the fewest incidents is North America. It could be our vigilance that is keeping terror attacks at bay. But it is also worth noting, as we observe the vast apparatus of searches and screening, that the Transportation Security Administration’s assistant administrator for global strategies has admitted that those expensive and cumbersome whole-body scanners have not resulted in the arrest of a single suspected terrorist. Not one.

Of course there are real threats out there, from sources including new branches of al-Qaeda and other such groups. And of course they will have to be battled, and those terrorists should be captured or killed. But we have done this before, and we can do so in the future under more normal circumstances. It will mean that the administration will have to be more careful — and perhaps have more congressional involvement — for certain actions, such as drone strikes. It might mean it will have to charge some of the people held at Guantanamo and try them in military or civilian courts.

In any event, it is a good idea that the United States find a way to conduct its anti-terrorism campaigns within a more normal legal framework, rather than rely on blanket wartime authority granted in a panic after Sept. 11.