Just out of curiosity - is it possible to determine where an atomic bomb was made after its explosion? That may be a technical problem and also an intelligence problem, but if it is possible to do that, why would deterrence not work with terrorists? Terrorists, from the perspective of a state, would have to be regarded as just another delivery system.
I gather that with biological agents it is indeed possible - and embarrassing - to find out where they were made.
Thiago
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