Vince, I think a lot of you, bro, but I really believe that you are being naive re. the interdiction of potential terrorist threats by LE. If that were so, they would be crowing about, as they were the possible attacks upon LAX.
If there is a message as to why there has not been more 'homeland' [god, how I hate that term] in-security, I belive it is only attributable to environment. But as our social clusters become more decentalized and less cohesive, the environment becomes more and more ripe.
Now, if you want to look at a very strange (sciologically) model, look at Israel, where the vast majority of the populace has done military service, and is either armed or is qualified to be so on short notice. Their crime model, IIRC, is about that of Britain. They have a divese society, with many languages and many more politcal positions thann you can count. But, by god, when it comes to threats to existence, they are cohesive.