Something else to consider.
I think that, proportional to the overall population, person-on-person violence is probably declining. Based on the stats in the book. In other words, if 5000 people were killed per year in the US in 1790 and 15,000 are killed in 2012, you're far less likely to get killed now, simply because it's 15,000 out of 300+ million.
However, there are still only 24 hours in a day. And, only a few hours are actually devoted to reporting news (even 24-hour stations only spend a few hours actually reporting NEW news, the rest of the time it's the same thing from a different talking head). Let's say your city had 50,000 people in 1950 and had 180 murders. Roughly every other night, there would be a report of a murder in the city on the news. By 2000, the population has increased to 125,000 while the murders have increased to 365. Well, now the news is reporting on it every single night, or perhaps even twice in one night. You'd think that the murder rate was going up. But, it's actually decreased.
Just saying that this might also be a factor in our "perception" of local violence.
Oh, as for the nuclear threat - I still remember (kinda - I grew up in the 80s, but had a dad who was a missile launch officer) what it felt like to absolutely KNOW that the Soviets were going to nuke us one day. Regardless of the actual chances of that happening, I remember thinking it was inevitable. However, there is no way that anyone is going to suitcase-nuke New Orleans. Sure, I know that it's possible. New Orleans being an importation hub, we might even make a short-list of cities likely to have it happen. But, the chance of anything like that happening, and of it happening here, and of it happening while I'm here, is so slim as to be inconsequential to my day-to-day thoughts.