An article in The Atlantic this month by Daniel Byman and Christine Fair makes the case that terrorists are, well, stupid. In general, most of their plots are small in scope and even those fail. They're essentially a ragtag bunch of fumbling morons - lucky for us.
I think this might be overstating it a bit - click through and read the comments after the article for a good debate - but it reminded me that I do make a related argument in my book. It's useful to remind ourselves that terrorists, by definition, are not as powerful as we think they are, or as powerful as they claim to be. (The entire reason to use terrorist tactics is because you're not strong enough to use conventional tactics.) So, our fears of terrorism and the reactions we've been taking as a country are practically guaranteed to be overblown.
Of course, you can counter with this argument: better safe than sorry, right? Better to overdo it than to be unprepared.
Not a bad point of course, but nevertheless, keeping the War on Terror expansive does have the nasty side effect of playing right into the terrorists' hands in terms of messaging. Treating them as powerful warriors makes them feel as such, and makes more recruitment possible.
A better attitude? Treat them as petty criminal scum. Vandals, not soldiers. A type of (loosely) organized crime, not a righteous army. The sort of group you'd have to be a nitwit to join up with.
(The Secret Peace delves into this in a lot more detail (hint, hint.))
Image by Frank Stockton