Eventually our borders will be closed... I just hope it doesn't take the destruction of one of our cities to do it.
This has been my concern. Nuclear material is out there, and it can be carried in small packages. We use TNT equivalent for ratings of nuclear bombs, but the truth is there is this is not a good comparison. The explosive power is just part of the destruction, how dirty the bomb is with radioactive particles is a major issue. We think of an area destroyed and then re rebuild. How about an area that you cannot even return to for 50 years. Nothing hypothetical just real possibility. Lets' hope we control the border before this happens.