I always assumed the reason for the intrusive security checks was that at some high level, our government felt another terror attack was very likely, and they d

I always assumed the reason for the intrusive security checks was that at some high level, our government felt another terror attack was very likely, and they didn't want anyone to be able to say they weren't doing anything after it happened again. So perhaps it is to prevent rioting in the streets after an attack as much as to prevent the attack itself.