What if they were Russian nukes that have been maintained properly?
During the Cold War the Russkies cached nukes in a number of Western countries for use by Spetznaz. They even smuggled nukes into CONUS.
What if the Russkies used Al Quaeda as a front in order to regain their superpower status? Nuke the USA and let the muslims take the blame. If the USA was nuked, the Russkies could use their arsenal to dominate Europe, Central Asia, and even China.
I was peripherally involved in the program to de-commission Russian nukes in the 1990s. There were so many holes in the process that it would have been easy for them to cheat and keep a large number of weapons.
Regarding the letter, maybe some Al Quaeda bit player wanted to get his 15 minutes of fame and spread a little terror. Maybe he was not authorized to threaten us; they have a problem with discipline among the crazies.
With Obama in office, the Russkies or Al Quaeda will not get a better shot at us.
I've heard that claim before. Do you think there is any truth to it? You can't just put a nuke in a farm shed in 1983 and leave it until 2011. Assuming they exist at all, either the Soviets recovered them, the US discovered them or someone is successfully mantaining them right under our noses. I just can't bring myself to believe in that last option, or the option I didn't even mention: that they were abandoned. They are just to valuable and politically dangerous to simply walk away from.