In spite of some high profile events, the actual threat of terrorism is exaggerated. You're far more likely to be impacted by things like traffic accidents and falls.
The reality is that the government in many instances creates the threats or exacerbates them, then crudely panics the public into approving increasingly intrusive measures to bolster security. At that point, well-connected security firms get lucrative contracts to implement overpriced measures that do hardly nothing to address any problems. It's like mobsters throwing a brick through a store window, then offering to provide "protection" against future brick-throwers.
One thing that constantly amazes me is how almost nobody is talking about this. Things get worse and worse and what do we hear people discussing? They are making small talk. People are more upset about George Zimmerman or about the gender of Kate and William's unborn royal baby than they are about becoming slaves in some Orwellian society that may be just around the corner. And that's the real threat to America.