Back of the Envelope

North Korea detonating nukes, Iran trying to get them, terrorists looking for a chance to use them against us. Some people think that it's not a case of if, but when, an American city will be struck by a nuclear weapon. Most people don't worry about it, though. I wonder why.

I know why I'm not overly worried, as I explained in this post on asteroid strikes, but not everyone shares my faith. Is everyone just so confident in God (whatever version they believe in), or are we overly complacent?