This is one of those things we should not lose sleep over. A truck or shipboard container, possibly.
Critical Mass is a non-negotiable figure, as are the well-known public details of implosion device assembly.
Just try to carry such a "briefcase".
Nope, I am going to worry about more immediate things.
Besides, our "No First Use" doctrine would be totally out the window if someone were to do this, and it would give us a blank check to do whatever we wanted. *WE* are not the ones who should be losing sleep over this.
We have one warhead for each WTC victim. Fact.
To use one, or even fifty against us would be the same thing as taking a knife to a gunfight.
Specially setting them off at ground level.
It may impress the Afghanis who love noise and flying dirt but in terms of real damage the most inefficient way to detonate one.
Of coure the psychological impact would be someting else and the sound of liberals and pacifists shouting "NUKE THE SOBs!!" will be defeaning.
Nonsense. They "negotiate" it with tritium. That allows them to get away with an otherwise subcritical amount of material in the guts of the device.