Terrorism is a nuisance, on a national scale. A very unpleasant nuisance, but for all that, your chances of being killed by a terrorist are very much less than of dying in some other violent way - for example, being killed in or by a car, or, in the case of Americans, through being shot.

It's possible to change things so as to reduce all those dangers, and obviously that's what has to be done. But the idea that somehow it's possible to get rid once and for all of these unpleasant feature of modern life - that's just not realistic. Politicians who pretend that they have the power to do that are just trying to fool people, and people who choose believe such promises are simply wanting to be fooled.